Classification
UPPE - Biological indicators of water pollution
21
LCO - Hydrobiology
6
UPP - Water pollution
3
UPT - Water pollution control and measurement
3
LCP - Limnology
2
LEL - Botany - lower plants
2
UPCE - Water chemistry
2
LGL - Zoology - general aspects
1
LVN - Food science - chemistry, analytics
1
UPC - Water - general aspects
1
UPN - Water protection, water quality, clean water
1
UUD - Ecotoxicology
1
UVF - Environmental aspects of heavy metals and their compounds
1