Hobbs, Marvin. <br/><br/>
Modern communications switching systems / 
by Marvin Hobbs. 
 - Blue Ridge Summit, Pa. :  G/L Tab Books,  1974. 
 - 276 p. :  ill. ;  22 cm. 
<br/><br/><label>ISBN: </label>0830646787 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Telephone, Automatic.<br/>Telephone switching systems, Electronic.<br/>Electric switchgear.