@Book{BVMC:230511, author = {Gullón, Ricardo}, title = {Francisco Ayala: "Los usurpadores." Editorial Sudamericana, Buenos Aires, 1949. 244 págs. 6 pesos}, publisher = {Alicante : Biblioteca Virtual Miguel de Cervantes, 2006}, year = {2006}, url = {https://www.cervantesvirtual.com/nd/ark:/59851/bmcqn6j1} }