APA (7th ed.) Citation

Beeching, N., Dance, D., Miller, A., & Spencer, R. (2002). Immunity conferred by smallpox vaccine - How long does immunity last? Reply.

Chicago Style (17th ed.) Citation

Beeching, N., D. Dance, A. Miller, and R. Spencer. Immunity Conferred by Smallpox Vaccine - How Long Does Immunity Last? Reply. 2002.

MLA (9th ed.) Citation

Beeching, N., et al. Immunity Conferred by Smallpox Vaccine - How Long Does Immunity Last? Reply. 2002.