Petrovska - Jovanović, S., K. Stojanova, and R. Miloševska. “Study of the Possibility for Chrome Separation and Concentration from Waste - Water by Lewatit S 1080 and Wofatit KPS”. Macedonian Journal of Ecology and Environment, vol. 2, no. 1, Aug. 1994, pp. 101-8, http://mjee.org.mk/index.php/mjee/article/view/15.