Polk affirms Monroe Doctrine. (2013). The History Channel website. Retrieved 5:14, May 22, 2013, from http://www.history.com/this-day-in-history/polk-affirms-monroe-doctrine.
Polk affirms Monroe Doctrine. [Internet]. 2013. The History Channel website. Available from: http://www.history.com/this-day-in-history/polk-affirms-monroe-doctrine [Accessed 22 May 2013].
“Polk affirms Monroe Doctrine.” 2013. The History Channel website. May 22 2013, 5:14 http://www.history.com/this-day-in-history/polk-affirms-monroe-doctrine.
“Polk affirms Monroe Doctrine,” The History Channel website, 2013, http://www.history.com/this-day-in-history/polk-affirms-monroe-doctrine [accessed May 22, 2013].
“Polk affirms Monroe Doctrine,” The History Channel website, http://www.history.com/this-day-in-history/polk-affirms-monroe-doctrine (accessed May 22, 2013).
Polk affirms Monroe Doctrine [Internet]. The History Channel website; 2013 [cited 2013 May 22] Available from: http://www.history.com/this-day-in-history/polk-affirms-monroe-doctrine.
Polk affirms Monroe Doctrine, http://www.history.com/this-day-in-history/polk-affirms-monroe-doctrine (last visited May 22, 2013).
Polk affirms Monroe Doctrine. The History Channel website. 2013. Available at: http://www.history.com/this-day-in-history/polk-affirms-monroe-doctrine. Accessed May 22, 2013.