www.psyking.net/id183.htm
muskingum.edu/~psych/psycweb/history/hall.htm#TimeLine
www.britannica.com/biography/G-Stanley-Hall
http://www.encyclopedia.com/topic/Granville_Stanley_Hall.aspx
muskingum.edu/~psych/psycweb/history/hall.htm#TimeLine
www.britannica.com/biography/G-Stanley-Hall
http://www.encyclopedia.com/topic/Granville_Stanley_Hall.aspx