Mathematician John Venn developed George Boole's symbolic logic and is best known for Venn diagrams, which pictorially represent the relations between sets.
John Venn. (2013). The Biography Channel website. Retrieved 02:56, Jun 20, 2013, from http://www.biography.com/people/john-venn-9517136.
John Venn. [Internet]. 2013. The Biography Channel website. Available from: http://www.biography.com/people/john-venn-9517136 [Accessed 20 Jun 2013].
"John Venn." 2013. The Biography Channel website. Jun 20 2013, 02:56 http://www.biography.com/people/john-venn-9517136.
"John Venn," The Biography Channel website, 2013, http://www.biography.com/people/john-venn-9517136 [accessed Jun 20, 2013].
"John Venn," The Biography Channel website, http://www.biography.com/people/john-venn-9517136 (accessed Jun 20, 2013).
John Venn [Internet]. The Biography Channel website; 2013 [cited 2013 Jun 20] Available from: http://www.biography.com/people/john-venn-9517136.
John Venn, http://www.biography.com/people/john-venn-9517136 (last visited Jun 20, 2013).
John Venn. The Biography Channel website. 2013. Available at: http://www.biography.com/people/john-venn-9517136. Accessed Jun 20, 2013.