An improved video-based computer tracking systems for soft biomaterials testing. - John Downs; Henry R. Halperin; Jay D. Humphrey; Frank C. P. Yin (IEEE Trans. Biomed. Eng., 1990)

Servo-controlled indenter for determining the transverse stiffness of ventricular muscle. - Henry R. Halperin; Joshua E. Tsitlik; Mark Gelfand; John Downs; Frank C. P. Yin (IEEE Trans. Biomed. Eng., 1991)