BOARDMAN, R. Free Library of Philadelphia Map Collection. Cartographic Perspectives, [S. l.], n. 25, p. 33, 1996. DOI: 10.14714/CP25.739. Disponível em: https://cartographicperspectives.org/index.php/journal/article/view/cp25-boardman. Acesso em: 28 apr. 2024.