LT revisited

http://www.velonews.com/train/articles/8217.0.html
"Finding your LT"

http://athlete-web.com/leaders/study_tr_ad_hr_02.html
http://athlete-web.com/sci_re_01.html
Good summary of AT,LT (in Japanese).

http://www.brianmac.demon.co.uk/coni.htm
http://www.brianmac.demon.co.uk/eval.htm
Conconi & various performance tests.