Abbasi, M. Y. GEORGE SALIBA. THE HISTORY OF AL—ṬABARÍ (TĀRĪKH AL—RUSUL WA’L—MULŪK), VOLUME XXVII, THE ABBASID REVOLUTION by JOHN ALDEN WILLIAMS;THE HISTORY OF AL—ṬABARĪ (TĀRĪKH—AL—RUSUL WA’L—MULŪK), VOL. XXXV, THE CRISIS OF THE ’ABBASID CALIPHATE . ISIRI 1987, 26, 75-76.