Esteban Romero-Frías; Liwen Vaughan (2012). "Exploring the Relationships Between Media and Political Parties Through web Hyperlink Analysis: The Case of Spain". Journal of the American Society for Information Science and Technology. 63 (5): 967–976. doi:10.1002/asi.22625. hdl:10481/48881.
Esteban Romero-Frías; Liwen Vaughan (2012). "Exploring the Relationships Between Media and Political Parties Through web Hyperlink Analysis: The Case of Spain". Journal of the American Society for Information Science and Technology. 63 (5): 967–976. doi:10.1002/asi.22625. hdl:10481/48881.
mediadb.eu
"Country Profile: Spain". Institute of Media and Communications Study. Retrieved 21 February 2015.