Willis, John Ralph, ed. (2018) [1979]. «Glossary». Studies in West African Islamic History, Volume 1: The Cultivators of Islam (1st edición). London and New York: Routledge. p. 197. ISBN9781138238534. «Kufr: Unbelief; non-Muslim belief (Kāfir = a non-Muslim, one who has received no Dispensation or Book; Kuffār plural of Kāfir).»
Morris, Benny (1999). Righteous victims: a history of the Zionist-Arab conflict, 1881-2001. Random House, Inc. p. [1]. ISBN978-0-679-42120-7.