APA aipamena

O'neill, G. K. (1981). A hopeful view of the human future. Jonathan Cape.

Chicago Style aipamena

O'neill, Gerard K. A Hopeful View of the Human Future. Jonathan Cape, 1981.

MLA aipamena

O'neill, Gerard K. A Hopeful View of the Human Future. Jonathan Cape, 1981.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.