Petrich, M. <br/><br/>
Rings and semigroups / 
Mario Petrich ; with an appendix by Richard Wiegandt. 
 - Berlin :  Springer-Verlag,  1974. 
 - viii, 182 p. ;  24 cm. 
 - Lecture notes in mathematics (Springer-Verlag) ;  380. .
<br/><br/>Bibliography : p. 168-174. 
<br/><br/><label>ISBN: </label>0387067302 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Semigroups.<br/>Associative rings.