Spectral theory / Lorch, Edgar Raymond. Spektralʹnai︠a︡ teorii︠a︡. English Lorch, Edgar Raymond. Spectral theory (Mathematics) QC20 .P7513 vol. 3 512.8 LOS Translation of Spektralʹnai︠a︡ teorii︠a︡. Includes bibliographical references. New York : Consultants Bureau, c1962. c1962. 1962 Text [12], 158 p. : ng engrus Topics in mathematical physics, v. 3 Problemy matematicheskoĭ fiziki. English ; v. 3.