Global anthropogenic temperature change correlates better with  total energy in world’s electricity grids (TWH)  than with total  atmospheric CO2.   Alternative title:  EEP (Energetic Particle Precipitation) the key to climate change.   By Dr Chris Barnes, Bangor Scientific and Educational Consultants email manager@bsec-wales.co.uk      First published online without  references August 2017. Revised version with multivariate analysis and references  March 2025.

Homepage http://drchrisbarnes.co.uk/

 

Abstract

Climate drivers are briefly discussed.  CO2 has been shown by some to be an insignificant  driver.  Solar irradiance theories are considered.  Solar magnetic and EEP aspects of climate are discussed in more detail.  It has been shown by others and see above that VLF transmissions from earth strongly influence the position of the  Van Allen Belts and hence the degree and influence of EEP on earth climate. The present hypothesis is thus that power grids modulate  EEP and would thus be expected to contribute  significantly to climate change.   Public domain data has been used to explore the multivariate correlation between global temperature, carbon dioxide levels in the atmosphere and  global energy of the power grid.  Initial exploration produced a statistically irrelevant model  Ŷ = 0.976531 + 0.0000590432 X1 - 0.00548928 X2 wherein X1 in 1000 TWH and X2 CO2 ppm, with some 2.58C of additional warming by 2050.    AI driven analysis advised disposal of X2.  Resultant algorithm  purely depends on TWH,     Ŷ = -0.751505 + 0.0000406276 X1 and yields  0.931C of extra warming only if electricity use expands to 67000 TWH by 2050.  The solar minimum of 2007–2010 was unusually deep and long lived. In the later stages of this period the electron fluxes in the radiation belts dropped to extremely low levels. The flux of relativistic electrons (>1 MeV) was significantly diminished.  This period was at the centre of the recent and so-called global warming hiatus and also coincided with one of Britain’s coldest ever winters.    The dynamics of the inner magnetosphere is strongly governed by the interactions between different plasma populations that are coupled through large-scale electric and magnetic fields, currents, and wave-particle interactions.  The precipitating inner magnetospheric particles influence the ionosphere and upper atmospheric chemistry and affect climate. Parasitic EM radiation from the power supply lines, when entering the ionosphere-magnetosphere system, might have an impact on the electron population in the radiation belt. Its interaction with trapped particles will change their energy and pitch angles; as a result particle precipitations might occur.  I conclude by suggesting that the results presented in this present study, which will doubtless be controversially received and criticised by some, goes a long way to enlightening the world of climate science on those very impacts.    In support of my findings (low R value for total energy consumed which is tantamount to CO2 emitted), Avakyan (2013) concludes the contribution of the greenhouse effect of carbon-containing gases to global warming turns out to be insignificant. climate warming would appear to be very highly  correlated with the total energy in the world’s power grids.  The more interlinked the grids, I would expect there them to radiate more efficiently into space and hence produce more EEP and more warming.    Interestingly and following the same hypothesis, so  called low carbon solutions and  sustainable   energy such as solar or wind power will not stop global warming  while ever it is on grid.

Thus the proposed solutions are :

1.       Remove all grid interconnections to reduce energy radiated into space.

2.       Put as many properties as possible self –sufficient in energy but ‘off-grid’ 

3.       Theoretically a pure DC power system with DC interconnectors would not radiate into space.  However, since AC/DC converters using solid state switching generate horrendous harmonic levels such radiation seems inevitable.

4.       Possible undergrounding of HV power may help but electromagnetically  screened enclosures would still be required which would be horrendously expensive.

5.       The above in no way detracts from the attractiveness of green energy technologies from the perspective of cleaner air and indeed if properly implemented at local residence level  would save massive costs in electricity and storage infrastructure.  

 

Introduction

There is absolutely no question that Earth’s climate is changing.  The recent two decades have contained some of the warmest years on record since modern records began. 

 

The usual argument advanced to explain the anthropogenic component of climate warming is that of increasing CO2.  

 

Although in a minority there are groups of scientists who dispute the CO2 connection.  For example, Avakyan (2013)[1] concludes the contribution of the greenhouse effect of carbon-containing gases to global warming turns out to be insignificant.

 

Another argument advanced by so called ‘climate deniers’ is that in  pre-industrialised eras  CO2 increases have often  lagged behind warming and that more than likely such increases were due to outgassing of the oceans.   The present author is not a climate denier but does aggressively question whether CO2 is the demonic driver it is has been framed to be.   This paper aims asks if there are other more relevant drivers.

 

 

If there were an  absence of any anthropogenic influence on climate, which must at this stage be a purely theoretical conjecture, one turns given the sun’s huge energy,  to solar irradiance as a climate driver.    Past     climate change may have been caused by the lowering of solar irradiation through two amplifying factors, namely (1) increased cosmic ray intensity, stimulating cloud formation and precipitation, and (2) reduced solar UV intensity, causing a decline of stratospheric ozone production and cooling because of less absorption of sunlight.  Accepting the idea of solar forcing of Holocene and Glacial climatic shifts has major implications for our view of present and future climate. It implies that the climate system is far more sensitive to small variations in solar activity than generally believed, see L. J. Gray et al. 2010 [2] , on the other hand conclude that solar luminosity changes are inadequate to account for recent climate change.  They cannot, however, rule out climate change because of the sun’s changed outputs in ultraviolet light and/or magnetised plasmas.   Zepp et al (2011)[3] discuss the effect of solar u/v on biogeochemical cycles as an accelerant to CO2,  in this way CO2 would  perhaps be expected to follow natural warming .   

 

If complex atmospheric chemistry and biogeochemistry solar amplification models are required  to link solar irradiance and climate then  perhaps one should look to solar magnetism for a more straightforward explanation.  The present author has recently show that earth’s climate is essentially magnetically  controlled via solar Ap,     see Barnes [4]. 

 

For example, rainfall peaks at geomagnetic solar minimum.  The hypothesis is stunningly simple. At this minimum GRB bursts are less deflected by the solar wind and hence there is more cloudiness and more chance of rainfall.    Planetary Ap values have been consistently falling for several decades, and it is likely this coupled with  QBO phase, which is caused, for example,  increased storminess and rainfall in the southern UK during the winter of 2013/14.    

 

This fall in Ap value is also consistent with the appearance of more and more persistent aircraft contrails in our skies and to some extent justifies my earlier conclusions with respect to contrails and their anthropogenic contributory factors in  what is in essence predominantly solar driven climate change.  If Ap  were to continue  to fall it is expected we might  see a  transition to a major and lengthy Maunder-like period of climate cooling.     

 

Courtillo et al (2007) [5] states that no forcing factor, be it changes in CO2 concentration in the atmosphere or changes in cosmic ray flux modulated by solar activity and geomagnetism, or possibly other factors, can at present be neglected or shown to be the overwhelming single driver of climate change in past centuries. Intensive data acquisition is required to further probe indications that the Earth's and Sun's magnetic fields may have significant bearing on climate change at certain time scales.

 

Seppala et al (2009) [6]  noted polar surface air temperatures which  were  significantly different at times of high and low  Ap .   In years where there were no sudden stratospheric warmings, the polar surface temperatures were up to 4C less when there was low  Ap,   whereas years with SSWs produce weaker correlations between geomagnetic activity and surface temperature change.    This is supportive of the  notion that low Ap    rather than increased CO2 is fuelling climate extremes.

 

Per the Intergovernmental Panel on Climate Change [IPCC, 2007] “More research to investigate the effects of solar behaviour on climate is needed before the magnitude of solar effects on climate can be stated with certainty.” While the IPCC focuses on the effects of changing solar irradiance, they also note that there might be other mechanisms through which the Sun can couple to the Earth's climate [IPCC, 2007, Chapter 1]. In this paper we utilize meteorological analyses to investigate the possible influence of variations in geomagnetic activity on SATs in both hemispheres.

 

Perhaps not surprisingly then, the UK Met Office are 'raising the roof' of their  Unified Model (UM) from 85 km to 100-140 km. At this increased altitude the impacts of space weather on atmospheric chemistry become more significant.  A significant component of space weather which has recently been found to influence earth weather and climate is energetic particle precipitation (EEP).

 

Energetic electron precipitation (EEP) from the Earth’s outer radiation belt continuously affects the chemical composition of the polar mesosphere. EEP can contribute to catalytic ozone loss in the mesosphere through ionization and enhanced production of odd hydrogen. However, the long-term mesospheric ozone variability caused by EEP has not been quantified or confirmed to date.

 

Seppala et al (2009)[6] predicted that EPP feedback would be complex, since strong vortices lead to large EPP effects due to NOx sequestration [Randall et al., 2007], but stratospheric warmings can also be followed by large EPP effects due to enhanced mesospheric descent [Siskind et al., 2007] [7].

 

 

Andersson et al (2014)  [8]  have shown  using observations from three different satellite instruments, that EEP events strongly affect ozone at 60–80 km, leading to extremely large (up to 90%) short-term ozone depletion. This impact is comparable to that of large, but much less frequent, solar proton events. On solar cycle timescales, they found that EEP causes ozone variations of up to 34% at 70–80 km. With such a magnitude, it is reasonable to suspect that EEP could be a very  important part of solar influence on the atmosphere and climate system.

 

 

Further they evaluated the influence of the galactic cosmic rays (GCR), solar proton events (SPE), and energetic electron precipitation (EEP) on chemical composition of the atmosphere, dynamics, and climate using the chemistry-climate model SOCOL. They  have carried out two 46-year long runs. The reference run was driven by a widely employed forcing set and, for the experiment run, and included additional sources of NOx and HOx caused by all considered energetic particles. Their results show that the effects of the GCR, SPE, and EEP fluxes on the chemical composition are most pronounced in the polar mesosphere and upper stratosphere; however, they are also detectable and statistically significant in the lower atmosphere consisting of an ozone increase up to 3 % in the troposphere and ozone depletion up to 8 % in the middle stratosphere.

 

The upshot is that  thermal effect of the ozone depletion in the stratosphere propagates down, leading to a warming by up to 1 K averaged over 46 years over Europe during the winter season. Thus, confirming EEP can affect atmospheric chemical composition, dynamics, and climate.

 

Natural  EEP  is associated with the Van Allen Belts ( AP Sousa -PhD Thesis 2018 )  and with pulsating aurorae, see Nishimura ( 2020) [9].

 

Anthropogenic effects on the space environment started in the late 19th century and reached their peak in the 1960s when high-altitude nuclear explosions were carried out by the USA and the Soviet Union. These explosions created artificial radiation belts near Earth that resulted in major damages to several satellites. Another, unexpected impact of the high-altitude nuclear tests was the electromagnetic pulse (EMP) that can have devastating effects over a large geographic area (as large as the continental United States). Other anthropogenic impacts on the space environment include chemical release experiments, high-frequency wave heating of the ionosphere and the interaction of VLF waves with the radiation belts,  see Gombosi et al  (2017) [10].

 

Van Allen Probes observations during the 17 March 2015 major geomagnetic storm strongly suggest that VLF transmitter-induced waves play an important role in sculpting the earthward extent of outer zone MeV electrons. A magnetically confined bubble of very low frequency (VLF) wave emissions of terrestrial, human-produced origin surrounds the Earth. The outer limit of the VLF bubble closely matches the position of an apparent barrier to the inward extent of multi-MeV radiation belt electrons near 2.8 Earth radii. When the VLF transmitter signals extend beyond the eroded plasmapause, electron loss processes set up near the outer extent of the VLF bubble create an earthward limit to the region of local acceleration near L = 2.8 as MeV electrons are scattered into the atmospheric loss cone, see Foster et al (2016) [11].

 

Present hypothesis

 

It has been shown by others and see above that VLF transmissions from earth strongly influence the position of the  Van Allen Belts and hence the degree and influence of EEP on earth climate.

 

The present author has previously commented elsewhere regarding radiation into space from the world’s    electricity power grids in relation to the acousto- magnetic phenomenon known as the Hum [4].  

 

The hypothesis is thus that power grids modulate  EEP and would thus be expected to contribute  significantly to climate change and at least have some part to play in any regression against temperature. .     However, electricity production only accounts for some 40-50% of fossil fuel energy burning and hence CO2 production worldwide.   If CO2 were the dominant climate driver and on the basis that other sources  are increasing at about the same rate as electricity production, one would expect CO2 to dominate in a regression against temperature.

 

Testing the Hypothesis   

Public domain data has been used to explore the correlation between global temperature since 1945 and global energy  TWH of the power grid and CO2 in the atmosphere.  A  Multiple Linear Regression analysis has been made using the  online calculator at Statistics Kingdom,   https://www.statskingdom.com/410multi_linear_regression.html

 

The Raw Data

 A black board with numbers and letters

AI-generated content may be incorrect.

 

Table 1

In raw data table  X1 =  Power in world’s electricity  grids  TWH since 1982-2015, 1982 and 5 year intervals thereafter  data from https://visualizingenergy.org/world-electricity-generation-since-1900/

    X2= Atmospheric CO2 ppm.      Y=  Earth’s SST  change, data from    https://climatereanalyzer.org/clim/sst_monthly/?dm_id=world_60s-60n&var_id=sstanom

 

Results

A multiple linear regression  analysis of the data above was made using the online calculator at  https://www.statskingdom.com/410multi_linear_regression.html

Despite X2 (CO2) having a much lower p-value,  .532  as opposed to 0.08 for X1 (TWH) it was included in the initial model  and astounding  can be seen to have a negative effect  on sea surface temperature  ( SST).   

 

The generated model is  Ŷ = 0.976531 + 0.0000590432 X1 - 0.00548928 X2.    ------Equation (1)

The following R code should produce the same results:

if(!"car" %in% installed.packages()){install.packages("car")}

library("car")

y<-c(-0.33,-0.46,-0.25,-0.2,0.12,0.26,0.07,-0.17)

x1<-c(8900,9950,12000,15000,21000,26000,18000,13500)

x2<-c(342.77,346.9,354.2,371.89,389,399,371.87,359.96)

model1 = lm(y~x1+x2)

summary(model1)

vif(model1)

 

Some estimates of electricity use  suggest a massive almost 3-fold increase by 2050.   Assuming stabilisation of C02 at present levels, Equation 1 yields 2.58C increase by 2050.  

This model is not however statistically significant,  and the advice of the AI generator was to remove X2 from the model.  

Allowing the system  to run automatically produces :

Ŷ = -0.751505 + 0.0000406276 X1………….Equation 2

Results of the multiple linear regression indicated that there was a very strong collective significant effect between the X1, X2, and Y, (F(1, 6) = 74.89, p < .001, R2 = 0.93, R2adj = 0.91).

 

Validation

 

    Residual normality

    linear regression assumes normality for residual errors. Shapiro Wilk p-value equals 0.9158. It is assumed that the data is normally distributed.

 

 

    Homoscedasticity - homogeneity of variance

    The White test p-value equals 0.260035 (F=1.784767). It is assumed that the variance is homogeneous.

 

    Multicollinearity - intercorrelations among the predictors (Xi)

    There is no multicollinearity concern as all the VIF values are smaller than 2.5 .

    Residuals are shown below:

 

 

A collage of graphs and diagrams

AI-generated content may be incorrect.

 

 

R Code

 

The following R code should produce the same results:

if(!"car" %in% installed.packages()){install.packages("car")}

library("car")

y<-c(-0.33,-0.46,-0.25,-0.2,0.12,0.26,0.07,-0.17)

x1<-c(8900,9950,12000,15000,21000,26000,18000,13500)

x2<-c(342.77,346.9,354.2,371.89,389,399,371.87,359.96)

model1 = lm(y~x1+x2)

summary(model1)

vif(model1)

 

Assuming an increase in electricity consumption to 67000 TWH world-wide by 2050 , equation 2 predicts 0.931 C increase in temperatures.      

 

Conclusions and Discussion

It can be clearly seen that the hypothesis is strongly supported.   This is a truly remarkable result given that in terms of fossil fuel burnt, electricity production only accounts for some 40-50% worldwide.  Being unaware of the above and given early historical theories and  earlier climate models it is easy to see how others would mistake CO2 as the main driver. 

 

The solar minimum of 2007–2010 was unusually deep and long lived. In the later stages of this period the electron fluxes in the radiation belts dropped to extremely low levels. The flux of relativistic electrons (>1 MeV) was significantly diminished.  This period was at the centre of the recent and so-called global warming hiatus and coincided with one of Britain’s coldest ever winters.   

 

The dynamics of the inner magnetosphere is strongly governed by the interactions between different plasma populations that are coupled through large-scale electric and magnetic fields, currents, and wave-particle interactions.  The precipitating inner magnetospheric particles influence the ionosphere and upper atmospheric chemistry and affect climate.

 

Colpitts et al (2016) [12]  present observations of higher-frequency (~50–2500 Hz, ~0.1–0.7 fce) wave modes modulated at the frequency of co-located lower frequency (0.5–2 Hz, on the order of fci) waves. These observations come from the Van Allen Probes Electric Field and Waves instrument's burst mode data and represent the first observations of coupling between waves in these frequency ranges. The higher-frequency wave modes, typically whistler mode hiss and chorus or magneto-sonic waves, last for a few to a few tens of seconds but are in some cases observed repeatedly over several hours. The higher-frequency waves are observed to be unmodulated before and after the presence of the electromagnetic ion cyclotron (EMIC) waves, but when the EMIC waves are present, the amplitude of the higher-frequency waves drops to the instrument noise level once every EMIC wave cycle. Such modulation could significantly impact wave-particle interactions such as acceleration and pitch angle scattering, which are crucial in the formation and depletion of the radiation belts.

 

DEMETER is a low orbiting satellite (660 km) which was operating for more than six years to study ionospheric perturbations in relation with seismic and anthropogenic activities. For this purpose, it recorded wave and plasma parameters all around the Earth (except in the auroral zones) at two different local times (10.30 and 22.30 LT). This paper will present an overview of the electromagnetic waves observed during sustained magnetic activity and then enhanced by a wave-particle interaction. Many different waves have been observed. It includes: - strange MLR (Magnetospheric Line Radiation) which have frequency lines close to the PLHR (Power Line Harmonic Radiation) at the harmonics of 50 (60) Hz but which are drifting in frequency, - waves such as hiss, chorus, QP (Quasi Periodic) emissions, triggered emissions, EMIC (Electromagnetic Ion Cyclotron) waves in the equatorial region, - emissions at the lower hybrid frequency, and - specific waves recorded during very intense magnetic activities or in particular regions (SAA, sub-auroral zones), see Parrot (2011)  [13].

 

Jing et al (2014) have discussed in detail the propagation of  PLHR in the ionosphere.

 

Vampola et al ( 1977) [14]  made a study  of electrons in the drift and bounce loss cones of the magnetospheric slot region. They  observed that discrete events account for the arrival of most electrons in the 100-400 keV range into the drift loss cone. Most such events originate from a high-power level VLF transmitter. Calculations of the loss rate caused by the events indicate that the electron flux in the slot region may decrease by as much as 50% per day. It is likely that wave-particle interaction occurs low on the field line due to the particle energies and wave frequencies. To transport particles to the lower interaction region, additional near-equator scattering, via power-line harmonic emissions or ELF hiss, may be required.

 

This stresses the overall importance of earth power systems in the EEP process. Volland also discusses the process in his book Atmospheric Electrodynamics (1984) [15] .   Rothkaehlet al (2004) [16]  recognises power lines as ‘one of the most important  sources of ‘Ionospheric disturbances generated by different natural processes and by human activity in Earth plasma’.

 

Luette et al. [1977] showed that chorus emissions tend to occur more frequently along longitudes that contain industrial centres which are located at high latitudes. They suggested that PLHR can stimulate chorus emissions through cyclotron resonance with trapped energetic electrons.

 

Pronenko et al (2014) [17]  conclude, parasitic EM radiation from the power supply lines, when entering the ionosphere-magnetosphere system, might have an impact on the electron population in the radiation belt. Its interaction with trapped particles will change their energy and pitch angles; as a result particle precipitations, might occur. Observations of EM emission by multiple low orbiting satellites have confirmed a significant increase in their intensity over the populated areas of Europe and Asia. Recently, there are many experimental evidences of the existence of power line harmonic radiation (PLHR) in the ionosphere. Their spectra consist of succession of 50 (60) Hz harmonics which is accompanied by a set of lines separated by 50 (60) or 100 (120) Hz - the central frequency of which is shifted to high frequency. These lines cover rather wide band - according to the available experimental data, their central frequencies are observed from ~1.5 - 3 kHz up to 15 kHz, and recently the main mains  frequencies and harmonics  are also observed.

 

The present author is not the only one to consider a link between electron precipitation and climate change.  The matter has been muted on by Tsurutani et al 2016 [18] who considered    heliospheric plasma sheet (HPS) impingement onto the magnetosphere as a cause of relativistic electron dropouts (REDs) via coherent EMIC wave scattering with possible consequences for climate change mechanisms.

 

Seinfield  and Pandis [19]  discuss atmospheric chemistry aspects of NOx and ozone. NOx is increased by electron precipitation. Direct effects of particles to both ionisation rates and chemical changes are now better understood for EPP/EEP.  

 

Seppala et al (2014)  [20]  in discussing ‘What is the solar influence on climate?  Overview of activities during CAWSES-II’ conclude that EEP causes  Strong indirect effects were observed in the stratosphere with further potential impacts on the troposphere. More studies are required to understand the EPP indirect effects on the tropospheric and surface climate.’

 

I conclude by suggesting that both the large  number of references to EEP, ELF and power systems cited above taken with  the results presented in this present study go an enormous  way to enlightening the world of climate science on those novel yet hugely  important impacts.   

 

It is possible that in addition to the growth of power systems there are also natural changing processes at work in the solid earth/atmosphere/climate system that are also altering EEP and global cloudiness etc.  I hope to report on these in the very near future. 

 

Proposed solution to XS warming in general

 

From the above results, recent  climate warming would appear to be very highly correlated with the total energy in the world’s power grids.  The more interlinked the grids, I would expect there them to radiate more efficiently into space and hence produce more EEP and more warming.   

 

Interestingly and following the same hypothesis, so called low carbon solutions and sustainable   energy such as solar or wind power will not stop global warming while ever it is on grid.

 

Thus, the proposed solutions are:

 

1.      Remove all grid interconnections to reduce energy radiated into space.

2.      Put as many properties as possible self –sufficient in energy but ‘off-grid’ 

3.      Theoretically a pure DC power system with DC interconnectors would not radiate into space.  However, since AC/DC converters using solid state switching generate horrendous harmonic levels such radiation seems inevitable.

4.      Possible undergrounding of HV power may help but electromagnetically screened enclosures would still be required which would be horrendously expensive.

The above in no way detracts from the attractiveness of green energy technologies from the perspective of cleaner air and indeed if properly implemented at local residence level  would save massive costs in electricity and storage infrastructure.  

 

References

1.      https://link.springer.com/article/10.1134/S1019331613030015

2.      https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2009RG000282

3.      https://pubs.rsc.org/en/content/articlelanding/2011/pp/c0pp90037k

4.      http://www.drchrisbarnes.co.uk/SOLARMAG.htm

5.      https://www.researchgate.net/publication/222817231_Are_there_connections_between_the_Earth%27s_magnetic_field_and_climate

6.      https://nora.nerc.ac.uk/id/eprint/11207/

7.      https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2007GL029293

8.      https://www.nature.com/articles/ncomms6197

9.      https://link.springer.com/article/10.1007/s11214-019-0629-3?wt_mc=Internal.Event.1.SEM.ArticleAuthorIncrementalIssue&utm_source=ArticleAuthorIncrementalIssue&utm_medium=email&utm_content=AA_en_06082018&ArticleAuthorIncrementalIssue_20200111&error=cookies_not_supported&code=369dbe56-4476-41c5-9267-f9c2f88b4b75

10.  https://www.researchgate.net/publication/309854824_Anthropogenic_Space_Weather

11.  https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016JA022509

12.  https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016GL071566

13.  https://ieeexplore.ieee.org/document/6051081

14.  https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/GL004i012p00569

15.  https://link.springer.com/book/10.1007/978-3-642-69813-2

16.  Ionospheric disturbances generated by different natural processes and by human activity in Earth plasma environment.  https://www.researchgate.net/publication/215972506_Ionospheric_disturbances_generated_by_different_natural_processes_and_by_human_activity_in_Earth_plasma_environment

17.  https://ui.adsabs.harvard.edu/abs/2014cosp...40E2630P/abstract

18.  https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016JA022499

19.  [BOOK] Atmospheric chemistry and physics: from air pollution to climate chang      JH Seinfeld, SN Pandis - 2016 - books.google.com

20.  https://link.springer.com/article/10.1186/s40645-014-0024-3