¸CAKMAK, Ali; YAYLI, Yusuf. On the parallel surfaces of the non-developable surfaces. Bulletin of the Karaganda University. Mathematics Series, [S. l.], v. 98, n. 2, p. 59–68, 2020. DOI: 10.31489/2020m2/59-68. Disponível em: https://mts.buketov.edu.kz/index.php/mathematics-vestnik/article/view/359. Acesso em: 4 sep. 2025.