TY  - BOOK
AU  -  Heyd,David  .
TI  - Supererogation : its status in ethical theory / 
T2  - Cambridge studies in philosophy, 
SN  - 0521239354
U1  - 170 
PY  - 1982///
CY  - Cambridge : 
PB  - Cambridge University Press , 
KW  - ETHICS
N1  - Includes bibliography and index
ER  -