Bulldog Information: Ca de Bou - History and origin of the breed, photographs. - http://www.bulldoginformation.com/presa-mallorquin.html
Molloser World: Ca de Bou - Breed history, facts, photographs, and links. - http://www.moloss.com/brd/cd/c002/
Spanish Club of the Ca de Bou - Organization and breed history, galleries, breeders, and schedule of events. English and Spanish. - http://www.cadebouspain.es/