Hughes, G. E. . <br/><br/>
A companion to modal logic /  
G. E. Hughes and M. J. Cresswell. 
 - NULL :   ill. ;   NULL .  
<br/><br/>NULL 
<br/><br/><label>ISBN: </label> NULL (Hb) 
<br/><br/><label>Subjects--Index Terms: </label>LOGIC 
<br/><br/><label>Dewey Class. No.: </label>160  / HUG/C