Saya mau tau Nota dari Paus Sixtus IV. Jelaskan dalam bahasa melayu

Vincenzo Pacifici,Un carme biografico di Sisto IV del 1477, Società Tiburtina di Storia e d'Arte, Tivoli, 1921

"The Historical Encyclopedia of World slavery", Editor Junius P. Rodriguez, ABC-CLIO, 1997,

"Black Africans in Renaissance Europe", Thomas Foster Earle, K. J. P. Lowe, Cambridge University Press, 2005,

"Christopher Columbus and the enslavement of the Amerindians in the Caribbean. (Columbus and the New World Order 1492–1992).", Sued-Badillo, Jalil, Monthly Review. Monthly Review Foundation, Inc. 1992. HighBeam Research. 10 Aug. 2009

"Castile, Portugal, and the Canary Islands: Claims and Counterclaims, 1344–1479", Joseph F. O'Callaghan, 1993, p. 287–310, Viator, Volume 24

"Variations of Popery", Samuel Edgar D.D. Internet Archive, Ebooks and Texts.