RANA, Pravanjan Kr. A STUDY OF THE GROUP OF COVERING TRANSFORMATION THROUGH FUNCTORS. Matematichki Bilten, [S. l.], v. 33, n. 1, p. 21–24, 2009. Disponível em: https://bilten.smm.org.mk/index.php/bilten/article/view/1748. Acesso em: 14 aug. 2026.