The open university  <br/><br/>
Algebraic structures  
by the open university  
 - Britian   The open university   1980 
 - 45p. :ills,  Pbk 
<br/><br/><label>ISBN: </label>0335059007 
<br/><br/><label>LC Class. No.: </label>QA.36.5.0611980