APA (7th ed.) Citation

Helfet, A. J., & Gruebel Lee, D. M. (1978). Disorders of the lumbar spine (2. print.). Lippincott.

Chicago Style (17th ed.) Citation

Helfet, Arthur J., and David M. Gruebel Lee. Disorders of the Lumbar Spine. 2. print. Philadelphia u.a: Lippincott, 1978.

MLA (9th ed.) Citation

Helfet, Arthur J., and David M. Gruebel Lee. Disorders of the Lumbar Spine. 2. print. Lippincott, 1978.