BLUMENTRITT, S. Design principles, biomechanical data and clinical experience with a polycentric knee offering controlled stance phase knee flexion : A preliminary report. J. Prosth. Orthot. 1997, 9, 1, 18-24
BLUMENTRITT, S. Transfemoral amputees walking on a rotary hydraulic prosthetic knee mechanism ; A preliminary report. J. Prosth. Orthot. 1998, 10, 3, 61-70