Classification
EFA - Petroleum, natural gas
46
CXRC - Natural gas
21
EWA - Energy economy
17
EFP - Petroleum production, natural gas production
9
GWBA - Raw material resources, raw material reserves
9
CXR - Natural gas and petroleum - chemistry and technology
8
EAD - Energy - comprehensive works
8
EBA - Energy production, energy technology
7
EFK - Petroleum deposits, natural gas deposits
7
EVA - Energy demand, energy supply - comprehensive works
7
GMP - Geochemical exploration
7
EXA - Energy policy
6
GDA - Engineering geology - general
6
CXA - Coal and fossil fuel - chemistry and technology
5
CXRH - Liquefied natural gas
5
EVN - Energy supply - future aspects
5
GWA - Raw material economy, raw material policy
5
TIJ - Furnaces, combustion plants
5
ECA - Energy resources
4
EFE - Petroleum geology
4
EFN - Petroleum exploration, natural gas exploration
4
ETF - Fuel cells - general
4
EVP - Energy models, energy system analysis
4
GAN - Geosciences - mathematical methods, computer applications
4
GCAA - Regional geology - Germany
4
GKK - Geophysics - applications
4
TKJ - Traffic
4
UEF - Sustainability
4
CAV - Chemicals, chemical reagents
3
CHRD - Gases and their properties
3
CLE - Combustion, flames, explosions
3
EAE - Energy - general
3
GWB - Raw materials - metals, nonmetals
3
TIA - Industrial engineering - general
3
CELC - Organic synthesis
2
CELD - Chemicals and reagents in organic synthesis
2
CHR - Chemistry of gases, liquids and melts
2
CHX - Chemical thermodynamics
2
CWA - Chemical engineering - reference books
2
CXRU - Synthetic fuels
2
EGA - Oil shale, oil sands
2
EHA - Renewable energy sources
2
ENA - Energy from biomass and waste
2
EVB - Energy supply of Germany
2
GHHF - Sedimentary basins
2
GMA - Geochemistry - general
2
GMAD - Organic geochemistry
2
GWAB - National raw material reports
2
TKB - Civil engineering - buildings
2
TKF - Power plants
2
more ...