Indian Railway standard specification for electro - mechanical selections for selective ringing on train traffic control circuits/ 
Railway Board, Ministry of Railways, India ; issued by Research Designs and Standars Organisation. 
 - Delhi :  Author,  1976. 
 - 13 p. ;  20 cm. 
 - IRSTC 7 - 76. .
<br/><br/><label>Dewey Class. No.: </label>625.165