Hughes, G. E. <br/><br/>
An introduction to modal logic 
<label>/ by </label> Hughes, G. E. 
<label>;</label> Cresswell, M. J. 
 - London  Methuen and Co. Ltd.  1977 
 - xi, 388p.  ill.   21 cm.  
<br/><br/><label>ISBN: </label>41629460X 
<br/><br/><label>Dewey Class. No.: </label>160  / HUG