by (India)B.N.Chakrabarty;by (USSR)I.M.Yonov...et al; by (USSR)S.G.Lekhnitskii;by (USSR)Y.G.Panovko...et al; by (USSR)N.N.Bogoliubov;by (USSR)N.N.Bogoliubov...et al; by (USSR)I.M.Yonov...et al;by (USSR)K.F.Pavlov...et al;