Ginsburg, Seymour,  1927- <br/><br/>
Studies in abstract families of languages/ 
by Seymour Ginsburg, Sheila Greibach [and] John Hopcroft. 
 - Providence, R.I.:  American Mathematical Society,  1969. 
 - iii, 51 p.:  26 cm. 
 - Memoirs of the American Mathematical Society;  no. 87 .
<br/><br/> Cover title. 
<br/><br/>Includes bibliographies. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Robots<br/>Machine theory.<br/>Programming (Electronic computers)