@misc{klapper_lake_restoration_1992, 
author={Klapper, H.},
title={Lake restoration under the economic conditions in the former GDR},
year={1992},
howpublished = {conference lecture: Barcelona (E); August 21-27, 1992},
note = {Online available at: \url{} (DOI). Klapper, H.: Lake restoration under the economic conditions in the former GDR. 25th Congress Sociatas Internationalis Limnologorum. Barcelona (E), 1992.}}