@Book{BVMC:292597, author = {Unamuno, Miguel de}, title = {Tarjeta de Unamuno a Rafael Altamira. Salamanca, 23 de febrero de 1896}, publisher = {Alicante : Biblioteca Virtual Miguel de Cervantes, 2012}, year = {2012}, url = {https://www.cervantesvirtual.com/nd/ark:/59851/bmcnk415} }