http://www.oxfordenlightenmnet.com/entry?=t173.e692
http://wwwoxfordmusiconline.com/subscriber/article/grove/music/30917
http://www.oxfordmusiconline.com/subscriber/article/grove/music/28231pg3
http://onlinebooks.library.upenn.edu/webbin/gutbook/lookup?num=6763
http://www.oxford-greecerome.com
http://Bartleby.com
http://www.bartleby.com/314/213.html
http://www.oxfordgreecerome.com
http://www.oxfordenlightenment.com/entry?=t173.e692
http://wwwoxfordmusiconline.com/subscriber/article/grove/music/30917