Bartholdt, Richard. The Interparliamentary Plan. Ely, Robert Erskine (編). Proceedings of the National Arbitration and Peace Congress New York, April 14th to 17th, 1907. New York: The National Arbitration and Peace Congress. 1907 [2019-06-04]. (原始內容存檔於2020-05-08).. Downloadable Google Books.
Grelling, Richard. The Crime. Gray, Sir Alexander (trans.). New York: George H. Doran Company. 1918 [2019-06-04]. ISBN 0-665-84477-8. (原始內容存檔於2020-05-09).
Vegetius: epitome of military science - Google Books. Books.google.com. [2011-03-13]. (原始內容存檔於2019-12-15). Vegetius has: Igitur qui desiderat pacem, praeparet bellum. ("Therefore he who desires peace, let him prepare war.")