TY - JOUR T1 - Understanding the consequences of GP referral thresholds: taking the instrumental approach JO - BMJ Quality & Safety UR - http://dx.doi.org/10.1136/bmjqs-2022-015557 PY - 2023/01/27 AU - Lewis J AU - Burton C ED - DO - DOI: 10.1136/bmjqs-2022-015557 PB - BMJ Y2 - 2024/12/22 ER -