RT Article T1 "Holosphyros?": A Byzantine Perception of "The God of Muhammad" JF Christian-Muslim encounters SP 109 OP 125 A1 Sahas, Daniel J. 1940- LA English PB Univ. Press of Florida YR 1995 UL https://ixtheo.de/Record/1847612717 SN 0813013593 SN 0813013569