Gray, M. D. Peter <br/><br/>
Logic, algebra and databases 
by Peter M. D. Gray 
 - Chichester  Ellis Horwood  1984 
 - 294p. 
 - Ellis horwood series in computers and their applications     .
<br/><br/><label>ISBN: </label>0470202599 
<br/><br/><label>Dewey Class. No.: </label>005.74  / N843;1