Classification
EFP - Petroleum production, natural gas production
86
GVA - Oceanography
8
CXRS - Petroleum
4
EWA - Energy economy
4
CXR - Natural gas and petroleum - chemistry and technology
3
EFA - Petroleum, natural gas
3
EFN - Petroleum exploration, natural gas exploration
3
EVA - Energy demand, energy supply - comprehensive works
3
EAA - Energy - reference books
2
EFK - Petroleum deposits, natural gas deposits
2
EGA - Oil shale, oil sands
2
GWBA - Raw material resources, raw material reserves
2
LTN - Biotechnology - biodegradation
2
CER - Macromolecular compounds - synthesis and reactions
1
CHRD - Gases and their properties
1
CWO - Separation and combination processes - mechanical
1
CXRC - Natural gas
1
CXRH - Liquefied natural gas
1
EVH - Energy supply - economic growth
1
GMAD - Organic geochemistry
1
GMP - Geochemical exploration
1
GWA - Raw material economy, raw material policy
1
GWD - Marine mineral resources
1
LTR - Bioreactor technology, fermentation
1
UCA - Environmental problems, man and environment - general aspects
1
UKE - Environment and energy resources
1