KARZHAUBAYEV, K. K. Modeling oil pollution of the Caspian Sea resulting from the Ural and Volga rivers input. International Journal of Mathematics and Physics, [S. l.], v. 7, n. 2, p. 30–35, 2016. Disponível em: https://ijmph.kaznu.kz/index.php/kaznu/article/view/201. Acesso em: 10 may. 2024.