Gawor, Łukasz, Szmatłoch, A. and Dolnicki, P. (2013) “Valorization of Post-mining Dumping Grounds as Geotourism Sites on the Example of the Ruhr Region”, Studies of the Industrial Geography Commission of the Polish Geographical Society, 24, pp. 106–118. doi: 10.24917/20801653.24.7.