Cita APA (7a ed.)

Scheel, R. L. (1987). Introduction to the future. ETC Publications.

Cita Chicago Style (17a ed.)

Scheel, Randall L. Introduction to the Future. Palm Springs, Calif.: ETC Publications, 1987.

Cita MLA (9a ed.)

Scheel, Randall L. Introduction to the Future. ETC Publications, 1987.