Cities of the Underworld 3: Hitler's Last Secret: Nazi Factory. (2013). The History Channel website. Retrieved 8:28, May 21, 2013, from http://www.history.com/shows/cities-of-the-underworld/videos/playlists/exclusives.
Cities of the Underworld 3: Hitler's Last Secret: Nazi Factory. [Internet]. 2013. The History Channel website. Available from: http://www.history.com/shows/cities-of-the-underworld/videos/playlists/exclusives [Accessed 21 May 2013].
“Cities of the Underworld 3: Hitler's Last Secret: Nazi Factory.” 2013. The History Channel website. May 21 2013, 8:28 http://www.history.com/shows/cities-of-the-underworld/videos/playlists/exclusives.
“Cities of the Underworld 3: Hitler's Last Secret: Nazi Factory,” The History Channel website, 2013, http://www.history.com/shows/cities-of-the-underworld/videos/playlists/exclusives [accessed May 21, 2013].
“Cities of the Underworld 3: Hitler's Last Secret: Nazi Factory,” The History Channel website, http://www.history.com/shows/cities-of-the-underworld/videos/playlists/exclusives (accessed May 21, 2013).
Cities of the Underworld 3: Hitler's Last Secret: Nazi Factory [Internet]. The History Channel website; 2013 [cited 2013 May 21] Available from: http://www.history.com/shows/cities-of-the-underworld/videos/playlists/exclusives.
Cities of the Underworld 3: Hitler's Last Secret: Nazi Factory, http://www.history.com/shows/cities-of-the-underworld/videos/playlists/exclusives (last visited May 21, 2013).
Cities of the Underworld 3: Hitler's Last Secret: Nazi Factory. The History Channel website. 2013. Available at: http://www.history.com/shows/cities-of-the-underworld/videos/playlists/exclusives. Accessed May 21, 2013.