Ergozhin, E. E., Tugelbaeva L. М., B. R. Tausarova, and R. K. Ashkeeva. 2013. “Complex Formation of Polyelectrolytes With Different Groups of Heavy and Transition Metal Ions”. International Journal of Biology and Chemistry 5 (1):44-48. https://ijbch.kaznu.kz/index.php/kaznu/article/view/81.