APA (7th ed.) Citation

Holmes, C. (2006). Why was Charles I executed? Continuum.

Chicago Style (17th ed.) Citation

Holmes, Clive. Why Was Charles I Executed? London, [England] ; New York, New York: Continuum, 2006.

MLA (9th ed.) Citation

Holmes, Clive. Why Was Charles I Executed? Continuum, 2006.