Indian standard sizes for squares holes for general enginnering purposes 
Indian Standards Institution 
 - New Delhi  Indian Standards Institution  1969 
 - 2p. 
<br/><br/> IS 2769 : 1969 
<br/><br/><label>Subjects--Topical Terms: </label><br/> Square Holes-Standards<br/> Standards <br/>NASA Thesaurus 
<br/><br/><label>Universal Decimal Class. No.: </label>083.7:621.472  / ISI