Nuclear Winter. (2013). The History Channel website. Retrieved 6:32, May 20, 2013, from http://www.history.com/shows/life-after-people/videos/playlists/how-might-people-disappear.
Nuclear Winter. [Internet]. 2013. The History Channel website. Available from: http://www.history.com/shows/life-after-people/videos/playlists/how-might-people-disappear [Accessed 20 May 2013].
“Nuclear Winter.” 2013. The History Channel website. May 20 2013, 6:32 http://www.history.com/shows/life-after-people/videos/playlists/how-might-people-disappear.
“Nuclear Winter,” The History Channel website, 2013, http://www.history.com/shows/life-after-people/videos/playlists/how-might-people-disappear [accessed May 20, 2013].
“Nuclear Winter,” The History Channel website, http://www.history.com/shows/life-after-people/videos/playlists/how-might-people-disappear (accessed May 20, 2013).
Nuclear Winter [Internet]. The History Channel website; 2013 [cited 2013 May 20] Available from: http://www.history.com/shows/life-after-people/videos/playlists/how-might-people-disappear.
Nuclear Winter, http://www.history.com/shows/life-after-people/videos/playlists/how-might-people-disappear (last visited May 20, 2013).
Nuclear Winter. The History Channel website. 2013. Available at: http://www.history.com/shows/life-after-people/videos/playlists/how-might-people-disappear. Accessed May 20, 2013.