APA (7th ed.) Citation

Loken, N. C., & Willoughby, R. J. Complete book of gymnastics.

Chicago Style (17th ed.) Citation

Loken, Newton C., and Robert J. Willoughby. Complete Book of Gymnastics.

MLA (8th ed.) Citation

Loken, Newton C., and Robert J. Willoughby. Complete Book of Gymnastics.

Warning: These citations may not always be 100% accurate.