M. J. Frissel, P. Poelstra, and N. van der Klugt. “The Contamination of Dutch Soils With Mercury and a Few Other Heavy Metals”. Netherlands Journal of Geosciences (January 1, 1974): 163-170. Accessed May 7, 2026. https://njgjournal.nl/index.php/njg/article/view/14447.