Mount Etna erupts. (2013). The History Channel website. Retrieved 3:32, May 22, 2013, from http://www.history.com/this-day-in-history/mount-etna-erupts.
Mount Etna erupts. [Internet]. 2013. The History Channel website. Available from: http://www.history.com/this-day-in-history/mount-etna-erupts [Accessed 22 May 2013].
“Mount Etna erupts.” 2013. The History Channel website. May 22 2013, 3:32 http://www.history.com/this-day-in-history/mount-etna-erupts.
“Mount Etna erupts,” The History Channel website, 2013, http://www.history.com/this-day-in-history/mount-etna-erupts [accessed May 22, 2013].
“Mount Etna erupts,” The History Channel website, http://www.history.com/this-day-in-history/mount-etna-erupts (accessed May 22, 2013).
Mount Etna erupts [Internet]. The History Channel website; 2013 [cited 2013 May 22] Available from: http://www.history.com/this-day-in-history/mount-etna-erupts.
Mount Etna erupts, http://www.history.com/this-day-in-history/mount-etna-erupts (last visited May 22, 2013).
Mount Etna erupts. The History Channel website. 2013. Available at: http://www.history.com/this-day-in-history/mount-etna-erupts. Accessed May 22, 2013.