U.S. Constitution signed. (2013). The History Channel website. Retrieved 5:36, June 19, 2013, from http://www.history.com/this-day-in-history/us-constitution-signed.
U.S. Constitution signed. [Internet]. 2013. The History Channel website. Available from: http://www.history.com/this-day-in-history/us-constitution-signed [Accessed 19 Jun 2013].
“U.S. Constitution signed.” 2013. The History Channel website. Jun 19 2013, 5:36 http://www.history.com/this-day-in-history/us-constitution-signed.
“U.S. Constitution signed,” The History Channel website, 2013, http://www.history.com/this-day-in-history/us-constitution-signed [accessed Jun 19, 2013].
“U.S. Constitution signed,” The History Channel website, http://www.history.com/this-day-in-history/us-constitution-signed (accessed Jun 19, 2013).
U.S. Constitution signed [Internet]. The History Channel website; 2013 [cited 2013 Jun 19] Available from: http://www.history.com/this-day-in-history/us-constitution-signed.
U.S. Constitution signed, http://www.history.com/this-day-in-history/us-constitution-signed (last visited Jun 19, 2013).
U.S. Constitution signed. The History Channel website. 2013. Available at: http://www.history.com/this-day-in-history/us-constitution-signed. Accessed Jun 19, 2013.