Svraka, I. et al. (2014) “Preconcentration of Metal Ions Using Silica Gel 60 F254”, Bulletin of Chemists and Technologists of Bosnia and Herzegovina, 42, pp. 11–16. Available at: https://www.glashem.pmf.unsa.ba/index.php/bctbh/article/view/120 (Accessed: 5 October 2026).