R. H. G. Bos, P. D. Jungerius, and A. J. Wiggers. 1971. “Solifluction and Colluviation on the Ice-Pushed Ridges of Uelsen, Kreis Grafschaft Bentheim, Germany”. Netherlands Journal of Geosciences, January, 751-54. https://njgjournal.nl/index.php/njg/article/view/14876.