How the Earth Was Made: Birth of the Earth. (2013). The History Channel website. Retrieved 12:15, May 25, 2013, from http://www.history.com/shows/how-the-earth-was-made/videos/playlists/.
How the Earth Was Made: Birth of the Earth. [Internet]. 2013. The History Channel website. Available from: http://www.history.com/shows/how-the-earth-was-made/videos/playlists/ [Accessed 25 May 2013].
“How the Earth Was Made: Birth of the Earth.” 2013. The History Channel website. May 25 2013, 12:15 http://www.history.com/shows/how-the-earth-was-made/videos/playlists/.
“How the Earth Was Made: Birth of the Earth,” The History Channel website, 2013, http://www.history.com/shows/how-the-earth-was-made/videos/playlists/ [accessed May 25, 2013].
“How the Earth Was Made: Birth of the Earth,” The History Channel website, http://www.history.com/shows/how-the-earth-was-made/videos/playlists/ (accessed May 25, 2013).
How the Earth Was Made: Birth of the Earth [Internet]. The History Channel website; 2013 [cited 2013 May 25] Available from: http://www.history.com/shows/how-the-earth-was-made/videos/playlists/.
How the Earth Was Made: Birth of the Earth, http://www.history.com/shows/how-the-earth-was-made/videos/playlists/ (last visited May 25, 2013).
How the Earth Was Made: Birth of the Earth. The History Channel website. 2013. Available at: http://www.history.com/shows/how-the-earth-was-made/videos/playlists/. Accessed May 25, 2013.