Roberts, S., Williams, J., Roberts, S., Ali, F., Cheung, W., Cohen, D., & Demery, G. (2007). The burden of disease, and the organisation and delivery of services for gastrointestinal and liver disorders: A review of the evidence. London: British Society of Gastroenterology.

Roberts, Stephen, J. Williams, S. Roberts, F. Ali, W. Cheung, D. Cohen, and G. Demery. The Burden of Disease, and the Organisation and Delivery of Services for Gastrointestinal and Liver Disorders: A Review of the Evidence. London: British Society of Gastroenterology, 2007.

Roberts, Stephen, et al. The Burden of Disease, and the Organisation and Delivery of Services for Gastrointestinal and Liver Disorders: A Review of the Evidence. London: British Society of Gastroenterology, 2007.