Margaret Mead Speaks at First Earth Day. (2013). The History Channel website. Retrieved 5:18, May 20, 2013, from http://www.history.com/speeches/margaret-mead-speaks-at-first-earth-day.
Margaret Mead Speaks at First Earth Day. [Internet]. 2013. The History Channel website. Available from: http://www.history.com/speeches/margaret-mead-speaks-at-first-earth-day [Accessed 20 May 2013].
“Margaret Mead Speaks at First Earth Day.” 2013. The History Channel website. May 20 2013, 5:18 http://www.history.com/speeches/margaret-mead-speaks-at-first-earth-day.
“Margaret Mead Speaks at First Earth Day,” The History Channel website, 2013, http://www.history.com/speeches/margaret-mead-speaks-at-first-earth-day [accessed May 20, 2013].
“Margaret Mead Speaks at First Earth Day,” The History Channel website, http://www.history.com/speeches/margaret-mead-speaks-at-first-earth-day (accessed May 20, 2013).
Margaret Mead Speaks at First Earth Day [Internet]. The History Channel website; 2013 [cited 2013 May 20] Available from: http://www.history.com/speeches/margaret-mead-speaks-at-first-earth-day.
Margaret Mead Speaks at First Earth Day, http://www.history.com/speeches/margaret-mead-speaks-at-first-earth-day (last visited May 20, 2013).
Margaret Mead Speaks at First Earth Day. The History Channel website. 2013. Available at: http://www.history.com/speeches/margaret-mead-speaks-at-first-earth-day. Accessed May 20, 2013.