Παραπομπή APA

(1970). 1971 Britannica yearbooks of science and the future. Encyclopaedia Britannica.

Παραπομπή Chicago Style

1971 Britannica Yearbooks of Science and the Future. Chicago: Encyclopaedia Britannica, 1970.

Παραπομπή MLA

1971 Britannica Yearbooks of Science and the Future. Encyclopaedia Britannica, 1970.