1. NHS England 2011 Developing the NHS Commissioning Board https://www.england.nhs.ukwp-contentuploadsDeveloping-the-commissioning-board.pdf
2. NHS England 2016 Clinical commissioning policy: bone conducting hearing implants (BCHIs) for hearing loss (all ages) https://www.england.nhs.uk/commissioning/wp-content/uploads/sites/12/2013/05/16041_FINAL.pdf
3. NHS Commissioning Board 2013 Clinical commissioning policy: Bone Anchored Hearing Aids https://www.england.nhs.uk/wp-content/uploads/2013/04/d09-p-a.pdf
4. PRISMA statement;Moher;Epidemiology,2011
5. GRADE: an emerging consensus on rating quality of evidence and strength of recommendations;Guyatt;BMJ,2008