Geochemistry of Bulgarian soils in villages affected and not affected by Balkan endemic nephropathy: a pilot study - Long, David T.; Icopini, Gary; Ganev, Varban; Petropoulos, Evangelos; Havezov, Ivan; Voice, Thomas; Chou, Karen; Spassov, Alexander; Stein, Aryeh (Nofer Institute of Occupational Medicine)