@Misc{BVMC:230905, author = {Álvarez Álvarez, Manuel}, author = {Urrutia Cárdenas, Hernán}, title = {El perfecto fuerte medieval (siglo XIII)}, publisher = {Alicante : Biblioteca Virtual Miguel de Cervantes, 2007}, year = {2007}, url = {https://www.cervantesvirtual.com/nd/ark:/59851/bmctq6b5} }