Gaya APA
Purtill, Richard L.. (1976).
Thinking about ethics .
New Jersey:
Prentice Hall.
Gaya Chicago
Purtill, Richard L..
Thinking about ethics.
New Jersey:
Prentice Hall,
1976.
Buku.
Gaya MLA
Purtill, Richard L..
Thinking about ethics.
New Jersey:
Prentice Hall,
1976.
Buku.
Gaya Turabian
Purtill, Richard L..
Thinking about ethics.
New Jersey:
Prentice Hall,
1976.
Buku.