APA (7th ed.) Citation
Ferguson, R. (2009). The Vikings: A History (1st Edition.). Penguin Books.
Chicago Style (17th ed.) Citation
Ferguson, Robert. The Vikings: A History. 1st Edition. New York: Penguin Books, 2009.
MLA (9th ed.) Citation
Ferguson, Robert. The Vikings: A History. 1st Edition. Penguin Books, 2009.
Warning: These citations may not always be 100% accurate.