KNIPPSCHILD, Robert. A waste of time and effort? Benefit and factors of success of cross-border cooperation in urban and regional development in the German-Polish-Czech triangle. Raumforschung und Raumordnung | Spatial Research and Planning, DE, v. 67, n. 3, p. 228–238, 2009. DOI: 10.1007/BF03183008. Disponível em: https://rur.oekom.de/index.php/rur/article/view/974. Acesso em: 15 aug. 2026.