The Library of Iberian Resources Online – Biblioteket for iberiske ressurser på nettet Baker, G.P. (1999): . Cooper Square Press. ISBN 0-8154-1005-0. Casson, Lionel (1991): , 2. utgave, Princeton University Press. ISBN 0-8154-1005-0. Lancel, Serge (1997): . Blackwell Publishers. ISBN 1-57718-103-4. Warry, John (1993): . Salamander Books Ltd. ISBN 1-56619-463-6.