1. The new Bell telephone;Sci. Am.,1877
2. The Bell system speakerphone;Clemency;AIEE. Trans.,1957
3. Seeking the ideal in ���hands-free��� telephony;Berkley;Bell Lab. Rec.,1974
4. Mod��le de laboratoire d'un poste t��l��phonique �� haut-parleur;Pays;FASE,1975
5. The hands-free telephone problem-an annotated bibliography;H��nsler;Signal Process.,1992