Cita APA (7th ed.)
Asimov, I. (1989). Frontiers: New discoveries about man and his planet, outer space, and the universe. Plume.
Cita Chicago (17th ed.)
Asimov, Isaac. Frontiers: New Discoveries About Man and His Planet, Outer Space, and the Universe. New York: Plume, 1989.
Cita MLA (9th ed.)
Asimov, Isaac. Frontiers: New Discoveries About Man and His Planet, Outer Space, and the Universe. Plume, 1989.
Atenció: Aquestes cites poden no estar 100% correctes.