Gorbachev resigns as president of the USSR. (2013). The History Channel website. Retrieved 10:21, May 19, 2013, from http://www.history.com/this-day-in-history/gorbachev-resigns-as-president-of-the-ussr.
Gorbachev resigns as president of the USSR. [Internet]. 2013. The History Channel website. Available from: http://www.history.com/this-day-in-history/gorbachev-resigns-as-president-of-the-ussr [Accessed 19 May 2013].
“Gorbachev resigns as president of the USSR.” 2013. The History Channel website. May 19 2013, 10:21 http://www.history.com/this-day-in-history/gorbachev-resigns-as-president-of-the-ussr.
“Gorbachev resigns as president of the USSR,” The History Channel website, 2013, http://www.history.com/this-day-in-history/gorbachev-resigns-as-president-of-the-ussr [accessed May 19, 2013].
“Gorbachev resigns as president of the USSR,” The History Channel website, http://www.history.com/this-day-in-history/gorbachev-resigns-as-president-of-the-ussr (accessed May 19, 2013).
Gorbachev resigns as president of the USSR [Internet]. The History Channel website; 2013 [cited 2013 May 19] Available from: http://www.history.com/this-day-in-history/gorbachev-resigns-as-president-of-the-ussr.
Gorbachev resigns as president of the USSR, http://www.history.com/this-day-in-history/gorbachev-resigns-as-president-of-the-ussr (last visited May 19, 2013).
Gorbachev resigns as president of the USSR. The History Channel website. 2013. Available at: http://www.history.com/this-day-in-history/gorbachev-resigns-as-president-of-the-ussr. Accessed May 19, 2013.