Hula-Hoop patented. (2013). The History Channel website. Retrieved 2:15, May 18, 2013, from http://www.history.com/this-day-in-history/hula-hoop-patented.
Hula-Hoop patented. [Internet]. 2013. The History Channel website. Available from: http://www.history.com/this-day-in-history/hula-hoop-patented [Accessed 18 May 2013].
“Hula-Hoop patented.” 2013. The History Channel website. May 18 2013, 2:15 http://www.history.com/this-day-in-history/hula-hoop-patented.
“Hula-Hoop patented,” The History Channel website, 2013, http://www.history.com/this-day-in-history/hula-hoop-patented [accessed May 18, 2013].
“Hula-Hoop patented,” The History Channel website, http://www.history.com/this-day-in-history/hula-hoop-patented (accessed May 18, 2013).
Hula-Hoop patented [Internet]. The History Channel website; 2013 [cited 2013 May 18] Available from: http://www.history.com/this-day-in-history/hula-hoop-patented.
Hula-Hoop patented, http://www.history.com/this-day-in-history/hula-hoop-patented (last visited May 18, 2013).
Hula-Hoop patented. The History Channel website. 2013. Available at: http://www.history.com/this-day-in-history/hula-hoop-patented. Accessed May 18, 2013.