Hahn, Jens, et al. “The Effect of Catchment Soils on Heavy Metal Concentrations in a Brook Situated in the Historic Mining Region of Braubach, Germany”. DIE ERDE – Journal of the Geographical Society of Berlin, vol. 149, no. 2-3, Sept. 2018, pp. 132-44, https://www.die-erde.org/index.php/die-erde/article/view/401.