I need to know a minimum of 5 pages on the history of horses.do you know where i should look

the hisory of horses

1: http://www.historyforkids.org/learn/environment/horses.htm
2: http://mysite.verizon.net/mmaidens/
3: http://www.amnh.org/exhibitions/horse/?section=evolution
4: http://en.wikipedia.org/wiki/Horse
5: http://www.horserides.org/history-of-horses.html