Predictors of non-response in a UK-wide cohort study of children's accelerometer-determined physical activity using postal methods
Carly Rich, Mario Cortina-Borja, Carol Dezateux, Marco Geraci, Francesco Sera, Lisa Calderwood, Heather Joshi, Lucy J Griffiths
BMJ Open Jan 2013, 3 (3) e002290; DOI: 10.1136/bmjopen-2012-002290