↑(angl.) Brown, Delmer and Ichiro Ishida, eds. (1979). Jien, c.1220, Gukanshō; "The Future and the Past: a translation and study of the 'Gukanshō,' an interpretive history of Japan written in 1219" translated from the Japanese and edited by Delmer M. Brown & Ichirō Ishida. Berkeley: University of California Press. ISBN 0-520-03460-0
↑Pyrrhus, Britannica, 2008, O. Ed.Pyrrhus: Main: king of Hellenistic Epirus whose costly military successes against Macedonia and Rome gave rise to the phrase „Pyrrhic victory.“ His Memoirs and books on the art of war were quoted and praised by many ancient authors, including Cicero.
↑Jones, Archer The art of war in the Western world, University of Illinois Press, Urbana,2001 page 32 isbn=0-252-06966-8