Ackermann, Robert John 1933-.
An introduction to many-valued logics /
by Robert Ackermann 
. - London : Routledge & Kegan Paul Ltd, New York : Dover Publications Inc,  1967 
. - 90 p.  18 cm. 
 - (Monographs in modern logic )
<br/>К.: Бібліогр. : c. 82-89, Index