Classification
UPVC - Groundwater
14
GTAK - Hydrogeology
10
UPK - Water resources, water supply
6
UPN - Water protection, water quality, clean water
6
GCAA - Regional geology - Germany
4
UPT - Water pollution control and measurement
4
UPVF - Surface waters - streams, rivers, lakes
4
UAN - Environment - mathematical methods, computer applications
2
UHN - Landscape ecology
2
UPC - Water - general aspects
2
UPP - Water pollution
2
UPV - Special waters
2
URA - Soil chemistry
1
USDE - Domestic waste, plastics, paper
1