Heyd,  David. <br/><br/>
Supererogation : its status in ethical theory. 
by David Heyd. 
 - Cambridge.  Cambridge University Press.  c1982 
 - (4),191p.;  22cm.- 
 - Cambridge studies in philosophy. .
<br/><br/><label>Dewey Class. No.: </label>170  /   HEY