Indian standard specification for black square bolts and nuts (diameter range 6 to 39 mm) and black square screws (diameter range 6 to 24mm) 
Indian Standards Institution 
 - New Delhi  Indian Standards Institution  1968 
 - 10p. 
<br/><br/> IS 2585 : 1968 
<br/><br/><label>Subjects--Topical Terms: </label><br/> Black Square Bolts <br/> Black Square Nuts<br/> Standards <br/>NASA Thesaurus 
<br/><br/><label>Universal Decimal Class. No.: </label>083.7:621.882.213  / ISI