“Maintenance of drainage networks; [Instandhaltung von Entwässerungsnetzen]”, gis.Business | issn : 1869-9286, vol. 16, no. 1, pp. 35–36, Jan. 2015, Accessed: Nov. 09, 2026. Available: https://journal-gis.business/index.php/gisb/article/view/508