Ancient Roman Aqueduct. (2013). The History Channel website. Retrieved 9:53, May 18, 2013, from http://www.history.com/shows/cities-of-the-underworld/videos/playlists/exclusives.
Ancient Roman Aqueduct. [Internet]. 2013. The History Channel website. Available from: http://www.history.com/shows/cities-of-the-underworld/videos/playlists/exclusives [Accessed 18 May 2013].
“Ancient Roman Aqueduct.” 2013. The History Channel website. May 18 2013, 9:53 http://www.history.com/shows/cities-of-the-underworld/videos/playlists/exclusives.
“Ancient Roman Aqueduct,” The History Channel website, 2013, http://www.history.com/shows/cities-of-the-underworld/videos/playlists/exclusives [accessed May 18, 2013].
“Ancient Roman Aqueduct,” The History Channel website, http://www.history.com/shows/cities-of-the-underworld/videos/playlists/exclusives (accessed May 18, 2013).
Ancient Roman Aqueduct [Internet]. The History Channel website; 2013 [cited 2013 May 18] Available from: http://www.history.com/shows/cities-of-the-underworld/videos/playlists/exclusives.
Ancient Roman Aqueduct, http://www.history.com/shows/cities-of-the-underworld/videos/playlists/exclusives (last visited May 18, 2013).
Ancient Roman Aqueduct. The History Channel website. 2013. Available at: http://www.history.com/shows/cities-of-the-underworld/videos/playlists/exclusives. Accessed May 18, 2013.