Mankind and Engineering. (2013). The History Channel website. Retrieved 8:40, May 19, 2013, from http://www.history.com/shows/mankind-the-story-of-all-of-us/videos/playlists/web-exclusives.
Mankind and Engineering. [Internet]. 2013. The History Channel website. Available from: http://www.history.com/shows/mankind-the-story-of-all-of-us/videos/playlists/web-exclusives [Accessed 19 May 2013].
“Mankind and Engineering.” 2013. The History Channel website. May 19 2013, 8:40 http://www.history.com/shows/mankind-the-story-of-all-of-us/videos/playlists/web-exclusives.
“Mankind and Engineering,” The History Channel website, 2013, http://www.history.com/shows/mankind-the-story-of-all-of-us/videos/playlists/web-exclusives [accessed May 19, 2013].
“Mankind and Engineering,” The History Channel website, http://www.history.com/shows/mankind-the-story-of-all-of-us/videos/playlists/web-exclusives (accessed May 19, 2013).
Mankind and Engineering [Internet]. The History Channel website; 2013 [cited 2013 May 19] Available from: http://www.history.com/shows/mankind-the-story-of-all-of-us/videos/playlists/web-exclusives.
Mankind and Engineering, http://www.history.com/shows/mankind-the-story-of-all-of-us/videos/playlists/web-exclusives (last visited May 19, 2013).
Mankind and Engineering. The History Channel website. 2013. Available at: http://www.history.com/shows/mankind-the-story-of-all-of-us/videos/playlists/web-exclusives. Accessed May 19, 2013.