Hind limb malformations in free-living northern leopard frogs (Rana pipiens) from Maine, Minnesota, and Vermont suggest multiple etiologies. - Meteyer CU; Loeffler IK; Fallon JF; Converse KA; Green E; Helgen JC; Kersten S; Levey R; Eaton-Poole L; Burkhart JG (Teratology, 2000)