@misc{levkov_framework_of_1989, 
author={Levkov, L.,Jacob, D.,Eppel, D. P.,Grassl, H.},
title={Framework of cloud parameterization including ice for 3-D mesoscale models},
year={1989},
howpublished = {GKSS report},
note = {Online available at: \url{} (DOI). Levkov, L.; Jacob, D.; Eppel, D.; Grassl, H.: Framework of cloud parameterization including ice for 3-D mesoscale models. GKSS 89-E-7. 1989.}}