De Luca, Aldo. <br/><br/>
Finiteness and regularity in semigroups and formal languages. 
Aldo De Luca. 
 - Heidelberg:  Springer-Verlag;  1999. 
 - x, 240p. 
<br/><br/><label>Subjects--Index Terms: </label>Semigroups. Formal languages. 
<br/><br/><label>Universal Decimal Class. No.: </label>512.53  / DEL