Petrich Mario <br/><br/>
Rings and semigroups 
Petrich Mario 
 - Berlin  Springer-Verlag           1974 
 - viii, 182p.  cm. 
 - Lecture Notes in Mahtematics; 380 .
<br/><br/><label>Standard No.: </label>20053 
<br/><br/><label>Source: </label> Textual 
<br/><br/><label>Dewey Class. No.: </label>B27, L4