@misc{guhr_water_quality_1992, 
author={Guhr, H.},
title={Water quality of the river Elbe},
year={1992},
howpublished = {conference lecture: Quebec (CDN); 07.-18.03.1992},
note = {Online available at: \url{} (DOI). Guhr, H.: Water quality of the river Elbe. Quebec (CDN), 1992.}}