@misc{wietstock_studies_in_1993, 
author={Wietstock, P., Witte, G.},
title={Studies in multiphase pumping with screw pumps},
year={1993},
howpublished = {conference lecture: Cannes (F);},
note = {Wietstock, P.; Witte, G.: Studies in multiphase pumping with screw pumps. In: 6th International Conference on Multi Phase Production. Cannes (F). 1993. 389-414.}}