Walking Reference Material: Image

 

Source: http://www.aibmaya.com/walk-cycles/

Orginal source Ricard Williams, The Animator's Survival Kit. A manual of methods, principles and formulas for classic, computer, games, stop motion and internet animators. 

http://www.amazon.co.uk/Animators-Survival-Kit-Richard-Williams/dp/0571238343/ref=sr_1_1?ie=UTF8&s=books&qid=1295254250&sr=8-1