Ecological, genetical and immunological consequences of the intense chemical load in the region of the Upper Kama potassium deposit / V. A. Demakov, N. N. Kevorkov, V. A. Chereshnev, B. A. Bachmetyev // Urban Ecology : proceeding of the International Symposium. - Didim : Ege University Press, 1991. - P. 419.