1. Ultrasonic Ranging System manual and handbook,1984
2. Qualitative sonar based environment learning for mobile robots;Mataric,1989
3. Steps towards triaural perception;Peremans,1991
4. Ahigh-resolution sensor based on tri-aural perception;Peremans;IEEE Trans. Robot. Autom.,1993
5. Accurate ranging of multiple objects using ultrasonic sensors;Audenaert,1991