Classification
AHZ - History of science and technology
1
ELA - Geothermal energy
1
GBA - General geology, historical geology
1
GDA - Engineering geology - general
1
GFA - Mineralogy - general
1
GXAB - Polar research - antarctic region
1
TKL - Mining - technical aspects
1
YBB - Law - general
1
YMA - International law
1