Classification
UPVC - Groundwater
6
GTAK - Hydrogeology
5
GCAA - Regional geology - Germany
2
UPK - Water resources, water supply
2
UPN - Water protection, water quality, clean water
2
UPT - Water pollution control and measurement
2
UPVF - Surface waters - streams, rivers, lakes
2
UAN - Environment - mathematical methods, computer applications
1
UHN - Landscape ecology
1
UPC - Water - general aspects
1
UPP - Water pollution
1
UPV - Special waters
1