Note 481 — Chapter IX · PROBLEMS OF THE ARABIAN CULTURE (C) PYTHAGORAS, MOHAMMED, CROMWELL
Charles Francis Atkinson translation
Kattenbusch, Lehrb. d. vgl. Konfessionsk., I (1892), pp. 234, et seq.; N. P. Milyukov, Skizz. russ. Kulturg. (1901) II, pp. 104, et seq.