Rylov, Maxim, and Andreas Reimer. “Pairwise Line Labeling of Geographic Boundaries: An Efficient and Practical Algorithm”. Cartographic Perspectives0, no. 79 (May 20, 2015): 5-21. Accessed September 25, 2021. https://cartographicperspectives.org/index.php/journal/article/view/cp79-rylov-reimer.