APA (7th ed.) Citation

Frechtling, D. C. (1976). Proposed standard definitions and classifications for travel research. United States Travel Data Center.

Chicago Style (17th ed.) Citation

Frechtling, Douglas C. Proposed Standard Definitions and Classifications for Travel Research. Washington, D.C: United States Travel Data Center, 1976.

MLA (9th ed.) Citation

Frechtling, Douglas C. Proposed Standard Definitions and Classifications for Travel Research. United States Travel Data Center, 1976.