W. Elzenga, J. Schwan, Y.A. Baumfalk, J. Vandenberghe, and L. Krook. “Grain Surface Characteristics of Periglacial Aeolian and Fluvial Sands”. Netherlands Journal of Geosciences, Jan. 1986, pp. 273-86, https://njgjournal.nl/index.php/njg/article/view/13149.