(NoHRANA PRIRODYs (NSPRAWO^NIKs - (NmITR@[KIN(B,(Nk(B. (Np(B.s (NkONSTANTIN pETROWI^s ((Nm(B.s (NaGROPROMIZDATs, 1987)
Keywords: (NoHRANA OKRUVA@]EJ SREDYs -- (NsPRAWO^NIKIs