Balstrøm, T. (1989) “Landslides: Extent and economic significance: proceedings of the 28. International Geological Congress: Symposium on Landslides, Washington, D.C., 17July 1989. Ed. by Earl E. Brabb & Betty L. Harrod”., Geografisk Tidsskrift, 89. Tilgængelig hos: https://tidsskrift.dk/geografisktidsskrift/article/view/44774 (Set: 5 december 2025).