1. A mechanism of acoustic echo formation;Freedman;Acústica,1962
2. Etude et réalization d'un dispositif multi-capteurs permettant la conduite automatique d'un assemblage sousmarin;Durand,1984
3. Adaptative ultrasonic range finder for robots;Martín;NATO Workshop Sensor Devices and Systems for Robotics, Costa Brava, Spain,1987
4. Medida precisa de distâncias mediante técnicas ultra-sônicas;Bastos;Controle & Instrumentaçâo,1989