@misc{hempel_mercury_contaminated_1991, 
author={Hempel, M.},
title={Mercury contaminated sites in Germany},
year={1991},
howpublished = {conference lecture: Burlington (CDN); 15.-18.04.1991},
note = {Online available at: \url{} (DOI). Hempel, M.: Mercury contaminated sites in Germany. Workshop on Biological Interactions of Metals and Organometals in the Environment. Burlington (CDN), 1991.}}