Ayubi, Nazih N.; Hashemi, Nader; Qureshi, Emran (2009). „Islamic State“. In Esposto, John L. (red.). The Oxford Encyclopedia of the Islamic World. Oxford: Oxford University Press.
Esposito, John L. (2014). „Islamic State“. The Oxford Dictionary of Islam. Oxford: Oxford University Press. „[Islamic State] Modern ideological position associated with political Islam.“
