Anabela Carvalho (2010). "Portugal: Media System"(PDF). The International Encyclopedia of Communication. Retrieved 14 April 2015.
wan-press.org
"World Press Trends"(PDF). World Association of Newspapers. Paris. 2004. Archived from the original(PDF) on 8 February 2015. Retrieved 15 February 2015.
web.archive.org
"World Press Trends"(PDF). World Association of Newspapers. Paris. 2004. Archived from the original(PDF) on 8 February 2015. Retrieved 15 February 2015.