@misc{mengelkamp_on_the_1988, 
author={Mengelkamp, H.-T.},
title={On the energy output estimation of wind turbines},
year={1988},
howpublished = {journal article,GKSS report},
note = {Online available at: \url{} (DOI). Mengelkamp, H.: On the energy output estimation of wind turbines. International Journal of Energy Research. 1988. vol. 12, 113-123.}}