Health impacts of free bus travel for young people: evaluation of a natural experiment in London
Phil Edwards, Rebecca Steinbach, Judith Green, Mark Petticrew, Anna Goodman, Alasdair Jones, Helen Roberts, Charlotte Kelly, John Nellthorp, Paul Wilkinson
J Epidemiol Community Health Aug 2013, 67 (8) 641-647; DOI: 10.1136/jech-2012-202156