Some maintenance features of "Strowger" automatic telephone systems : Strowger automatic telephones / Automatic Telephone Manufacturing Company Ltd.
The 32A selector : B.P.O. type 2,000 / Automatic Telephone Manufacturing Company Ltd.
Rede digital com integração de serviços / Telecom Portugal; Direcção Comercial
Eléments de téléinformatique / SCOM; Ministère du Budget