Classification
EFA - Petroleum, natural gas
318
EGA - Oil shale, oil sands
68
EWA - Energy economy
15
ECA - Energy resources
13
CWE - Chemical engineering, chemical industry - general
7
CXR - Natural gas and petroleum - chemistry and technology
7
GMAD - Organic geochemistry
7
CXRH - Liquefied natural gas
6
CXRS - Petroleum
5
GWBA - Raw material resources, raw material reserves
5
YAE - Law, economy, social affairs - general
5
CXRC - Natural gas
4
EEA - Coal - general
4
CXA - Coal and fossil fuel - chemistry and technology
3
EAA - Energy - reference books
3
EFP - Petroleum production, natural gas production
3
EHA - Renewable energy sources
3
GAN - Geosciences - mathematical methods, computer applications
3
GWA - Raw material economy, raw material policy
3
GWB - Raw materials - metals, nonmetals
3
TIA - Industrial engineering - general
3
EFK - Petroleum deposits, natural gas deposits
2
GBHB - Geology of continental shelves
2
GHH - Sedimentary petrography - general
2
GKK - Geophysics - applications
2
GMP - Geochemical exploration
2
TIJ - Furnaces, combustion plants
2
TKB - Civil engineering - buildings
2
TKJ - Traffic
2
AFK - Research institutions - Germany
1
CRHS - Isotope separation and enrichment
1
CTL - Thermal analysis
1
CXM - Coal combustion
1
CXRU - Synthetic fuels
1
DPA - Electronic data processing - applications
1
DYA - Artificial intelligence
1
EBA - Energy production, energy technology
1
EFE - Petroleum geology
1
EFN - Petroleum exploration, natural gas exploration
1
ENA - Energy from biomass and waste
1
EVA - Energy demand, energy supply - comprehensive works
1
EXA - Energy policy
1
GBAH - Stratigraphy, history of earth
1
GBEN - Tectonics
1
GDA - Engineering geology - general
1
GHA - Petrology - general
1
GHHD - Sedimentary transport, sedimentation
1
GHM - Sedimentary rocks
1
GHMB - Sandstone, conglomerate
1
GHMK - Salt deposits, evaporites
1
more ...