by (USSR)A.O.Gelfond;by (United States)A.H.Nayfeh; by (USSR)A.V.Efimov;by (United States)M.Mandl; by (USSR)I.Duncan; (United States)C.Payne; by (USSR)D.N.Trifonov;by (United States)L.K.Williams; by (USSR)A.M.Prokhorov;by (United States)M.A.Omar; by (USSR)V.S.Vladimirov;by (United States)A.G.Webster; by (USSR)A.Ramakrishnan;by (United States)C.Harper; by (USSR)A.I.Busev; (United States)G.L.Clark; by (USSR)A.Starkov;by (United States)K.Sandberg; by (USSR)V.Nabokov;by (United States)V.Nabokov;