International Patent Classification 1979 :  Class and subclass titles , synopsis of classesand subclasses with information on the number of subdivisions 

 - 3. Ed. 
 - 128 s. 
<br/><br/> 16.457-16.484 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Internationale Patentklassifikation