Understanding and optimising patient and public involvement in trial oversight: an ethnographic study of eight clinical trials oleh K. D. Coulman, A. Nicholson, A. Shaw, A. Daykin, L. E. Selman, R. Macefield, G. W. Shorter, H. Cramer, M. R. Sydes, C. Gamble, M. E. Pick, G. Taylor, J. A. Lane