1. Ryder et al 1994 UK Six months or more 60 148
2. Chen et al 2003
3. Roberts and Bateman 1995 UK All PPI prescribing in a defined period 41 GP practices
4. Rubin et al 1995 UK >12 months 24 400
5. Goudie et al 1996 UK Repeat prescribing register 15 495