The End of the World. (2013). The History Channel website. Retrieved 11:58, May 23, 2013, from http://www.history.com/shows/cities-of-the-underworld/videos/playlists/.
The End of the World. [Internet]. 2013. The History Channel website. Available from: http://www.history.com/shows/cities-of-the-underworld/videos/playlists/ [Accessed 23 May 2013].
“The End of the World.” 2013. The History Channel website. May 23 2013, 11:58 http://www.history.com/shows/cities-of-the-underworld/videos/playlists/.
“The End of the World,” The History Channel website, 2013, http://www.history.com/shows/cities-of-the-underworld/videos/playlists/ [accessed May 23, 2013].
“The End of the World,” The History Channel website, http://www.history.com/shows/cities-of-the-underworld/videos/playlists/ (accessed May 23, 2013).
The End of the World [Internet]. The History Channel website; 2013 [cited 2013 May 23] Available from: http://www.history.com/shows/cities-of-the-underworld/videos/playlists/.
The End of the World, http://www.history.com/shows/cities-of-the-underworld/videos/playlists/ (last visited May 23, 2013).
The End of the World. The History Channel website. 2013. Available at: http://www.history.com/shows/cities-of-the-underworld/videos/playlists/. Accessed May 23, 2013.