Gosh you guys! It's all online now ;--) Here's a couple:
http://www.listenhear.co.uk/general_acoustics.htm
http://www.tnt-audio.com/topics/frequency_e.html
.
http://www.listenhear.co.uk/general_acoustics.htm
http://www.tnt-audio.com/topics/frequency_e.html
.