by (USSR)V.Lakshmikantham;by (United Kingdom)E.T.Copson; by (USSR)A.Yariv;by (United Kingdom)J.M.Ziman; by (USSR)H.M.Srivastava;by (United Kingdom)K.Rektorys; by (USSR)V.A.Ugarov;by (United Kingdom)C.M.Will; by (USSR)V.M.Potapov;by (United Kingdom)O.B.Ramasy; by (USSR)A.S.Kompaneyets;by (United Kingdom)E.Leader; by (USSR)A.Starkov;by (United Kingdom)A.Sharp; by (USSR)G.A.Sudzilovstij;by (United Kingdom)P.R.Webb; by (USSR)I.S.Dmitriev;by (United Kingdom)P.W.Atkins; by (USSR)I.V.Petrynov;by (United Kingdom)J.G.Stark;