Classification
UPN - Water protection, water quality, clean water
11
UPVF - Surface waters - streams, rivers, lakes
GTA - Hydrology - general
2
UPK - Water resources, water supply
2
GCAA - Regional geology - Germany
1
LCO - Hydrobiology
1
UHN - Landscape ecology
1
UPCE - Water chemistry
1
UPT - Water pollution control and measurement
1
UXAH - Radioisotopes in water
1