APA (7e ed.) Bronvermelding

Helmer-Hirschberg, O. (1967). Analysis of the future: The delphi method. The Rand Corporation.

Chicago (17e ed.) Bronvermelding

Helmer-Hirschberg, Olaf. Analysis of the Future: The Delphi Method. Sta. Monica, Ca: The Rand Corporation, 1967.

MLA (9e ed.) Bronvermelding

Helmer-Hirschberg, Olaf. Analysis of the Future: The Delphi Method. The Rand Corporation, 1967.