GRIGOREVA, T. I. Invariant Geometric Objects of the Canonical Almost-Geodesic Mapping π2 (e = 0). Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 54, n. 10, p. 1329–1335, 2002. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4171. Acesso em: 5 dec. 2025.