Manuel Sintubin. “Structural and Paleogeographic Inferences from a Texture Analysis of Ordovician and Silurian Pelites of the Wepion Borehole (Ardennes, Belgium)”. Netherlands Journal of Geosciences, vol. 72, Jan. 1994, pp. 305-10, https://njgjournal.nl/index.php/njg/article/view/12516.