Authors: Philip Tideman; Anne W Taylor; Edward Janus; Ben Philpot; Robyn Clark; Elizabeth Peach; Tiina Laatikainen; Erkki Vartiainen; Rosy Tirimacco; Alicia Montgomerie; Janet Grant; Vincent Versace; James A Dunbar Journal: BMJ Open Date: 2013-08-23 Impact factor: 2.692