ROSSMAN, P. Comparison of speed of sound and ultrasound attenunation in the os calcis of bone density of the radius, femur and lumbar spine,. Clin Phys Physiol Meas. 1989, 10, 353-360
REAS, H. Broadband ultrasound attenuation: A new diagnostic method in osteoporosis,. AJR. 1990, 155, 825-828