Dreisbach, Christopher.
Study guide to accompany Barker: the elements of logic /
Christopher Dreisbach, Robert J. Cavalier 
. - 5th edition 
. - New York : McGraw-Hill Book Company,  1989 
. - vii, 167 p.  tab., schem.  25 cm. 
<br/><label>  ISBN: </label>0-07-003732-9