(NnATURALXNYJ KAU^UK (B:s (Nw (B2-(NH ^(B. /s - (NrOBERTS(B, (Na(B.s; (NwYSOCKIJ(B, (Nz(B.(Nz(B.s ((NmOSKWA (B:s (NmIR(B,s, 1990)
(N~(B. 1 (656 (NS(B., (NIL(B.)s (N~(B. 2 ( 720 (NS(B., (NIL(B.)s
Keywords: (NkAU^UKs