I think it was from a this Tmag article:
comparison of the values found here:
Swinton PA, Stewart A, Agouris I, Keough JWL, and Lloyd R. A biomechanical analysis of straight and hexagonal barbell deadlifts using submaximal loads. J Strength Cond Res. 2011b. J Strength Cond Res. 25(7) 2000-9.
and found here:
Cormie, P, McCaulley, GO, Triplett, TN, and McBride, JM. Optimal loading for maximal power output during lower-body resistance exercises. Med Sci Sports Exerc. 39: 340–349, 2007.
Winchester, JB, Erickson, TM, Blaak, JB, and McBride, JM. Changes in bar-path kinematics and kinetics after power-clean training. J Strength Cond Res. 19: 177–183, 2005.
Garhammer, J. Power production by Olympic weightlifters. 1980. Med Sci Sports Exerc. 12(1):54-60.