@Book{BVMC:788987, author = {Unamuno, Miguel de}, title = {Carta de Miguel de Unamuno a Manuel Ugarte. 14 de abril de 1901 }, publisher = {Alicante : Biblioteca Virtual Miguel de Cervantes, 2017}, year = {2017}, url = {https://www.cervantesvirtual.com/nd/ark:/59851/bmcsx8d4} }