Hughes G E <br/><br/>
Companion to modal logic. 

 - New York     Methuen        1984 
 - xvii,203p.  cm. 
<br/><br/><label>Standard No.: </label>44846 
<br/><br/><label>Source: </label> Textual 
<br/><br/><label>Dewey Class. No.: </label>R141, M4