Ahadzadeh, Ali, et al. “DETERMINATION AND INVESTIGATION OF POLLUTION OF THE NIR RIVER IN ARDABIL PROVINCE OF IRAN”. Proceedings of the YSU B: Chemical and Biological Sciences, vol. 46, no. 1 (227), Mar. 2012, pp. 59-63, doi:10.46991/PYSU:B/2012.46.1.059.