Stevens, P. J., Keen, J. E., Crowther, P. A., Okell, M., & Wilkins, F. (1948). National Health Service.

Stevens, Peter J., J. E. Keen, P. A. Crowther, M. Okell, ja F. Wilkins. National Health Service. 1948.

Stevens, Peter J., et al. National Health Service. 1948.