APA (7th ed.) Citation

Harris, R., Frankel, L. J., & Harris, S. (1977). Guide to Fitness After Fifty. Springer US.

Chicago Style (17th ed.) Citation

Harris, Raymond, Lawrence J. Frankel, and Sara Harris. Guide to Fitness After Fifty. Boston, MA: Springer US, 1977.

MLA (9th ed.) Citation

Harris, Raymond, et al. Guide to Fitness After Fifty. Springer US, 1977.