“APPLICATION OF MODIFIED SORBENTS BASED ON POLYACRYLONITRILE FIBER IN THE PURIFICATION OF NATURAL WATERS FROM COPPER IONS”. JournalNX - A Multidisciplinary Peer Reviewed Journal, vol. 7, no. 03, Mar. 2021, pp. 183-6, https://repo.journalnx.com/index.php/nx/article/view/2751.