Massive oil spill begins in Gulf of Mexico. (2013). The History Channel website. Retrieved 5:04, May 21, 2013, from http://www.history.com/this-day-in-history/massive-oil-spill-begins-in-gulf-of-mexico.
Massive oil spill begins in Gulf of Mexico. [Internet]. 2013. The History Channel website. Available from: http://www.history.com/this-day-in-history/massive-oil-spill-begins-in-gulf-of-mexico [Accessed 21 May 2013].
“Massive oil spill begins in Gulf of Mexico.” 2013. The History Channel website. May 21 2013, 5:04 http://www.history.com/this-day-in-history/massive-oil-spill-begins-in-gulf-of-mexico.
“Massive oil spill begins in Gulf of Mexico,” The History Channel website, 2013, http://www.history.com/this-day-in-history/massive-oil-spill-begins-in-gulf-of-mexico [accessed May 21, 2013].
“Massive oil spill begins in Gulf of Mexico,” The History Channel website, http://www.history.com/this-day-in-history/massive-oil-spill-begins-in-gulf-of-mexico (accessed May 21, 2013).
Massive oil spill begins in Gulf of Mexico [Internet]. The History Channel website; 2013 [cited 2013 May 21] Available from: http://www.history.com/this-day-in-history/massive-oil-spill-begins-in-gulf-of-mexico.
Massive oil spill begins in Gulf of Mexico, http://www.history.com/this-day-in-history/massive-oil-spill-begins-in-gulf-of-mexico (last visited May 21, 2013).
Massive oil spill begins in Gulf of Mexico. The History Channel website. 2013. Available at: http://www.history.com/this-day-in-history/massive-oil-spill-begins-in-gulf-of-mexico. Accessed May 21, 2013.