Slope Display on a Locomotion Interface. - David Tristano; John M. Hollerbach; Robert R. Christensen (ISER, 1999)

Torso Force Feedback Realistically Simulates Slope on Treadmill-Style Locomotion Interfaces. - John M. Hollerbach; Rose Mills; David Tristano; Robert R. Christensen; William B. Thompson; Yangming Xu (Int. J. Robotics Res., 2001)