Petrich, Mario. <br/><br/>
Rings and semigroups. 
With an appendix by Richard Wiegandt. 
 - Berlin,  New York,  Springer-Verlag,  1974. 
 - viii, 182 p. 
 - Lecture notes in mathematics, 380 .
<br/><br/><label>ISBN: </label>0387067302 (New York) 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Semigroups.<br/>Associative rings.
<br/><br/><label>Universal Decimal Class. No.: </label>512.53  / PET