Willis, John Ralph, ed. (2018) [1979]. «Glossary». Studies in West African Islamic History, Volume 1: The Cultivators of Islam 1.ª ed. Londres e Nova Iorque: Routledge. 197 páginas. ISBN9781138238534. Kufr: Unbelief; non-Muslim belief (Kāfir = a non-Muslim, one who has received no Dispensation or Book; Kuffār plural of Kāfir).
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books.google.pt
Bunt, Gary (2009). iMuslims. [S.l.]: The Other Press. p. ccxxiv. Consultado em 27 de agosto de 2015
