International patent classification 
/ WIPO 
 - Geneva:   WIPO,   1994 
 - 6th ed. .
<br/><br/>Vol. 7 (Section G: Physics); ISBN: 92-805-0508-4; 172p. 
<br/><br/><label>ISBN: </label>92-805-0508-4 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Library science
<br/><br/><label>Subjects--Index Terms: </label>Patent classification 
<br/><br/><label>Universal Decimal Class. No.: </label>D 025.4PATENt N4.7