Classification
GHA - Petrology - general
52
GCAC - Regional geology - noneuropean countries
5
GBA - General geology, historical geology
4
GFA - Mineralogy - general
4
EFE - Petroleum geology
3
GBEN - Tectonics
3
GHF - Igneous rocks, metamorphic rocks
3
GHH - Sedimentary petrography - general
3
GMK - Geochemistry of elements, minerals, rocks
3
GBAH - Stratigraphy, history of earth
2
GBEC - Geomorphology
2
GBH - Marine geology
2
GCAB - Regional geology - european countries
2
GHAB - Rocks - physical properties
2
GNA - Geology - soil sciences
2
GVA - Oceanography
2
CXA - Coal and fossil fuel - chemistry and technology
1
EEA - Coal - general
1
EFA - Petroleum, natural gas
1
EFK - Petroleum deposits, natural gas deposits
1
GAN - Geosciences - mathematical methods, computer applications
1
GBAK - Paleontology
1
GBEU - Weathering
1
GBHC - Ocean floor - sediments, morphology
1
GCA - Regional geology
1
GCAA - Regional geology - Germany
1
GDAA - Engineering geology - textbooks
1
GFAA - General mineralogy
1
GHM - Sedimentary rocks
1
GHMA - Clay, shale
1
GKA - Geophysics - general
1
GMAD - Organic geochemistry
1
GWAA - Raw material programs
1
GWB - Raw materials - metals, nonmetals
1