How the Earth Was Made: The Rockies. (2013). The History Channel website. Retrieved 9:13, June 19, 2013, from http://www.history.com/shows/how-the-earth-was-made/videos/playlists/.
How the Earth Was Made: The Rockies. [Internet]. 2013. The History Channel website. Available from: http://www.history.com/shows/how-the-earth-was-made/videos/playlists/ [Accessed 19 Jun 2013].
“How the Earth Was Made: The Rockies.” 2013. The History Channel website. Jun 19 2013, 9:13 http://www.history.com/shows/how-the-earth-was-made/videos/playlists/.
“How the Earth Was Made: The Rockies,” The History Channel website, 2013, http://www.history.com/shows/how-the-earth-was-made/videos/playlists/ [accessed Jun 19, 2013].
“How the Earth Was Made: The Rockies,” The History Channel website, http://www.history.com/shows/how-the-earth-was-made/videos/playlists/ (accessed Jun 19, 2013).
How the Earth Was Made: The Rockies [Internet]. The History Channel website; 2013 [cited 2013 Jun 19] Available from: http://www.history.com/shows/how-the-earth-was-made/videos/playlists/.
How the Earth Was Made: The Rockies, http://www.history.com/shows/how-the-earth-was-made/videos/playlists/ (last visited Jun 19, 2013).
How the Earth Was Made: The Rockies. The History Channel website. 2013. Available at: http://www.history.com/shows/how-the-earth-was-made/videos/playlists/. Accessed Jun 19, 2013.