VYHOVS'KA, I. Yu.; ZELINSKII, Yu. B.; STEFANCHUK, M. V. Generalized convex sets and the problem of shadow. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 67, n. 12, p. 1658–1666, 2015. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/2098. Acesso em: 27 apr. 2025.