1. Sykes J B . The Concise Oxford Dictionary. 6th ed. Oxford: Oxford University Press, 1976.
2. Walonick D . Survival Statistics Edition. 6th ed. StatPac Incorporated, 2013.
3. Mertens D . Research and Evaluation in Education and Psychology. Sage, 2015.
4. Busby M C, Burke F J T, Matthews R, Cytra J and Mullins A . The development of a concise questionnaire designed to measure perceived outcomes on the issues of greatest importance to patients. Br Dent J 2012; 212: 382–383.
5. Busby MC . Measuring success in dental practice using patient feedback. Birmingham: University of Birmingham, 2011. Available online at
http://etheses.bham.ac.uk/1288/1/Busby_MPhil_11.pdf
(accessed September 2015)