@misc{friedrich_a_high_1989, 
author={Friedrich, H.,Wagner, V.,Wille, P.},
title={A high performance neutron velocity selector},
year={1989},
howpublished = {journal article},
note = {Online available at: \url{} (DOI). Friedrich, H.; Wagner, V.; Wille, P.: A high performance neutron velocity selector. Physica  B. 1989. vol. 156-157, 547-549.}}