Veraart, C., Wanet, MC., & Mehauden, C. (1984). Improvement in Assessment of Direction and Distance, By Blind Subjects Using An Ultrasonic Prosthesis. Archives Internationales de Physiologie et de Biochimie, 92(2), P6-P7. https://doi.org/10.3109/13813458409071122 (Original work published 1984)