VOLCHKOV, V. V. On the Pompeiu problem and its generalizations. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 45, n. 10, p. 1444–1448, 1993. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5949. Acesso em: 5 dec. 2025.