Lumberyards. (2013). The History Channel website. Retrieved 8:49, May 24, 2013, from http://www.history.com/shows/modern-marvels/videos/playlists/great-inventions.
Lumberyards. [Internet]. 2013. The History Channel website. Available from: http://www.history.com/shows/modern-marvels/videos/playlists/great-inventions [Accessed 24 May 2013].
“Lumberyards.” 2013. The History Channel website. May 24 2013, 8:49 http://www.history.com/shows/modern-marvels/videos/playlists/great-inventions.
“Lumberyards,” The History Channel website, 2013, http://www.history.com/shows/modern-marvels/videos/playlists/great-inventions [accessed May 24, 2013].
“Lumberyards,” The History Channel website, http://www.history.com/shows/modern-marvels/videos/playlists/great-inventions (accessed May 24, 2013).
Lumberyards [Internet]. The History Channel website; 2013 [cited 2013 May 24] Available from: http://www.history.com/shows/modern-marvels/videos/playlists/great-inventions.
Lumberyards, http://www.history.com/shows/modern-marvels/videos/playlists/great-inventions (last visited May 24, 2013).
Lumberyards. The History Channel website. 2013. Available at: http://www.history.com/shows/modern-marvels/videos/playlists/great-inventions. Accessed May 24, 2013.