@misc{wilken_mercury_analysis_1993, 
author={Wilken, R.-D.},
title={Mercury analysis: a special example of species analysis},
year={1993},
howpublished = {GKSS report},
note = {Wilken, R.: Mercury analysis: a special example of species analysis. Fresenius Journal of Analytical Chemistry. 1993. vol. 342, 795-801.}}