Building the Towers. (2013). The History Channel website. Retrieved 10:51, May 18, 2013, from http://www.history.com/videos/building-the-towers.
Building the Towers. [Internet]. 2013. The History Channel website. Available from: http://www.history.com/videos/building-the-towers [Accessed 18 May 2013].
“Building the Towers.” 2013. The History Channel website. May 18 2013, 10:51 http://www.history.com/videos/building-the-towers.
“Building the Towers,” The History Channel website, 2013, http://www.history.com/videos/building-the-towers [accessed May 18, 2013].
“Building the Towers,” The History Channel website, http://www.history.com/videos/building-the-towers (accessed May 18, 2013).
Building the Towers [Internet]. The History Channel website; 2013 [cited 2013 May 18] Available from: http://www.history.com/videos/building-the-towers.
Building the Towers, http://www.history.com/videos/building-the-towers (last visited May 18, 2013).
Building the Towers. The History Channel website. 2013. Available at: http://www.history.com/videos/building-the-towers. Accessed May 18, 2013.