Ullman, Jeffrey D., <br/><br/>
Principles of database systems / 
Jeffrey D. Ullman. 
 - Potomac, Md :  Computer Science Press,  1980. 
 - 379 pages :  illustration ;  24 cm 
 - Computer software engineering series .
<br/><br/> Includes index 
<br/><br/>Bibliography: p. 360-371 
<br/><br/><label>ISBN: </label>0914894137  19.95 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Data base management