by (United States)O.K.Friedrichs;by (United States)P.R.Halmos; by (United States)I.Singer;by (United States)P.R.Halmos; by (United States)D.E.Ostenrock;by (United States)P.Halpern; by (United States)N.C.Giri;by (United States)P.E.Green; by (United States)O.V.Rudenko;by (United States)C.M.Harris; by (United States)C.O.Harris;by (United States)P.E.Popov; by (United States)E.G.Harris;by (United States)P.G.Hewitt; by (United States)H.F.Meiners;by (United States)P.N.Okeke; by (United States)J.D.Hart;by (United States)P.B.High; by (United States)R.Osborn;by (United States)P.Hall;