Coll Gilabert, Antonio (1981). De profesión periodista [On the Journalist Profession] (in Spanish). Editorial Noguer. p. 209. ISBN9788427938649. Retrieved 19 August 2018 – via Google Books.
León Gross, Teodoro (1 January 1996). El artículo de opinión [The Opinion Article] (in Spanish). Ariel. p. 118. ISBN9788434412736. Retrieved 19 August 2018 – via Google Books.
elmundo.es
Alas, Leopoldo (12 June 1994). "A la caza" [Hunting]. El Mundo (in Spanish). Madrid. Archived from the original on 6 November 2008. Retrieved 19 August 2018.
Alas, Leopoldo (12 June 1994). "A la caza" [Hunting]. El Mundo (in Spanish). Madrid. Archived from the original on 6 November 2008. Retrieved 19 August 2018.