TY  - BOOK
AU  - Book,Ronald V.
ED  - Conference on Formal Language Theory
TI  - Formal language theory: perspectives and open problems 
SN  - 0121153509 :
U1  - 164 
PY  - 1980///
CY  - New York
PB  - Academic Press
KW  - Formal languageses
N1  - Includes bibliographical references and index
ER  -