Cita APA (7th ed.)
Vernon, R. L. The Space Frontiers. Signet : New American Library.
Cita Chicago (17th ed.)
Vernon, Roger Lee. The Space Frontiers. Nueva York, EUA: Signet : New American Library.
Cita MLA (9th ed.)
Vernon, Roger Lee. The Space Frontiers. Signet : New American Library.
Atenció: Aquestes cites poden no estar 100% correctes.