@misc{rikowski_membrantechnik__1999, 
author={Rikowski, E.},
title={Membrantechnik},
year={1999},
howpublished = {lecture: Paderborn; 17.05.-20.05.1999},
note = {Online available at: \url{} (DOI). Rikowski, E.: Membrantechnik. Paderborn, 1999.}}