Indian Standards Institution <br/><br/>
Indian standard graphical symbols used in electrotechnology part X measuring instruments  electrotechnical standards sectional committee, ETDC 1 

 - Indian Standards Institution, New Delhi  1970 
 - 18 
<br/><br/><label>Dewey Class. No.: </label>IS:2032(pt.X)-1969 621.374 I.S.I.