Gaya APA
DUNCAN, D, J. (1979).
PROGRAMMED LEARNING AID FOR RETAILING: Modern Concepts and Practices .
California:
RICHARD D IRWIN.
Gaya MLA
DUNCAN, DELBERT, J.
"PROGRAMMED LEARNING AID FOR RETAILING: Modern Concepts and Practices".
California:
RICHARD D IRWIN,
1979.
Text.