ASHYRALYEV, Ch.; OZTURK, B. Some approximations of second order derivatives complex-valued functions. Bulletin of the Karaganda University. Mathematics Series, [S. l.], v. 91, n. 3, p. 17–23, 2018. DOI: 10.31489/2018m3/17-23. Disponível em: https://mts.buketov.edu.kz/index.php/mathematics-vestnik/article/view/198. Acesso em: 9 jul. 2025.