1. NHS Information Centre Hospital episode statistics for England Outpatient statistics, http://www.hesonline.nhs.uk/Ease/servlet/ContentServer?siteID=1937&categoryID=890 (accessed 2 May 2013).
2. General practitioner referral rates to district psychiatry and psychology services;Creed;Br J Gen Pract,1990
3. Psychiatric referral rates and the influence of on-site mental health workers in general practice;Ashworth;Br J Gen Pract,2002
4. A successful demand management initiative of referrals to a regional allergy clinic;Kaminski;Clin Exp Allergy,2011
5. Prioritisation of vascular outpatient appointments cannot be based on referral letters alone;Patel;Surgeon,2008