Hughes, George Edward <br/><br/>
Introduction to modal logic 
George Edward Hughes 
 - London :  Methuen,  1968. 
 - xii, 388p. :  ill. ;  23 cm. 
<br/><br/>Includes bibliographical references 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Modality (Logic)
<br/><br/><label>LC Class. No.: </label>BC199.M6H8