Citazione Stile APA (7a Edizione)

Spencer, R., & Jansen, J. J. G. (2012). Did Muhammad exist?: An inquiry into Islam's obscure origins. ISI Books.

Citazione stile Chigago Style (17a edizione)

Spencer, Robert, e Johannes J. G. Jansen. Did Muhammad Exist?: An Inquiry into Islam's Obscure Origins. Wilmington, Delaware: ISI Books, 2012.

Citatione MLA (9a ed.)

Spencer, Robert, e Johannes J. G. Jansen. Did Muhammad Exist?: An Inquiry into Islam's Obscure Origins. ISI Books, 2012.