Constitución de las instalaciones telefónicas automáticas : tomo I: Equipos y funcionamiento / Kurt Trautmann; Siemens
Guidance to the installation of telephone / Automatic Telephone & Electric Co. Ltd
The layout of "Strowger" automatic exchanges : Strowger automatic telephones / Automatic Telephone Manufacturing Company Ltd.
Some maintenance features of "Strowger" automatic telephone systems : Strowger automatic telephones / Automatic Telephone Manufacturing Company Ltd.