Popkorn, Sally <br/><br/>
First Steps in Modal Logic / 
Sally Popkorn 
 - Cambridge :  Cambridge University Press,  c1994. 
 - xiii, 314p. 
<br/><br/><label>ISBN: </label>9780521057936 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Modality
<br/><br/><label>Dewey Class. No.: </label>511.3  / PopF