Karzhaubayev KK. Modeling oil pollution of the Caspian Sea resulting from the Ural and Volga rivers input. Int. j. math. phys. [Internet]. 2016 Dec. 26 [cited 2024 Nov. 23];7(2):30-5. Available from: https://ijmph.kaznu.kz/index.php/kaznu/article/view/201