Mitchell, Bridger M., <br/><br/>
Utilization of the U.S telephone network / 
Bridger M. Mitchell, Tenzing Donyo. 
 - xv, 52 pages :  illustrations ;  28 cm. 
 - Rand ;  MR-436-EAC/WIK .
 - Rand ;  MR-436-EAC/WIK .
<br/><br/><label>Subjects--Topical Terms: </label><br/>Telephone--United States.<br/> Communication and traffic.