Telephony. 

 - Chicago 3 :  Telephony publishing Corp,  1983. 
 - v. :  ilus ;  28 cm. 
<br/><br/>V.204 No.4. V.204 No.9. V.204 No.13. V.204 No.17. V.204 No.21. V.204 No.26. V.203 No.9. V.205 No.14. V.205 No.14 Parte 2.