APA (7th ed.) Citation
Johnson, T. H. (1966). The companion to american history. Oxford university press.
Chicago Style (17th ed.) Citation
Johnson, Thomas H. The Companion to American History. New york: Oxford university press, 1966.
MLA (9th ed.) Citation
Johnson, Thomas H. The Companion to American History. Oxford university press, 1966.
Warning: These citations may not always be 100% accurate.