@misc{klapper_low_cost_1993, 
author={Klapper, H.},
title={Low cost technologies for water quality management in the former GDR},
year={1993},
howpublished = {conference paper,conference lecture: Stresa (I); 1993},
note = {Online available at: \url{} (DOI). Klapper, H.: Low cost technologies for water quality management in the former GDR. In: 5th International Conference on the Conservation and Management of Lakes. Stresa (I). 1993. 133-136.}}