Authors: Stephen Campbell; David Reeves; Evangelos Kontopantelis; Elizabeth Middleton; Bonnie Sibbald; Martin Roland Journal: N Engl J Med Date: 2007-07-12 Impact factor: 91.245
Authors: Pauline Boeckxstaens; Delphine De Smedt; Jan De Maeseneer; Lieven Annemans; Sara Willems Journal: BMC Health Serv Res Date: 2011-08-31 Impact factor: 2.655