The special considerations which enter into the determina-tlon of the credibility of historical statements are discussed,with considerable fullness, in Hereford B. George, Histori-aal evidence, Oxford, 1909; Allen Johnson, Hhtorian andhistorical evidence, New York, 1926; and Charles G. Crump,Hwtory and historical reeearch, London, 1928. The studentwill receive some aid in handltng the roblems of conflictingauthorities by using Frederic Doncalf and August C. Krey,Parallel source p r o b l e m in medieval history, New York andLondon, 1912 [Harper‘s parallel aource problems], or one ofthe other volumes in the same series.