@article{Afanasyev_2019 author = {S. O. Afanasyev}, title = {Problems and Progress of Investigations of Hydroecosystems' Ecological State in View of Implementation of EU Environmental Directives in Ukraine}, journal = {Hydrobiological Journal}, issn = {0018-8166}, year = {2019}, volume = {55}, number = {2}, pages = {3--17} }