Szőke, A., T. Mátyás, D. Szabó, L. Gerzson, and E. Forró. “Method for the Rapid Determination of Soil Physical Parameters of Extensive Green Roofs”. Review on Agriculture and Rural Development, vol. 2, no. 1, Jan. 2013, pp. 62-67, https://analecta.hu/index.php/rard/article/view/13283.