Professional codes of ethics.

MLA

Heijder, Alfred, and Herman van Geuns. Professional Codes of Ethics. London: Amnesty International Publications, 1976.

APA

Heijder, A., & van Geuns, H. (1976). Professional codes of ethics. London: Amnesty International Publications.

Chicago

Heijder, Alfred, and Herman van Geuns. Professional Codes of Ethics. London: Amnesty International Publications, 1976.