@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 = {Friedrich, H.; Wagner, V.; Wille, P.: A high performance neutron velocity selector. Physica  B. 1989. vol. 156-157, 547-549.}}