Physical working conditions as covered in European monitoring questionnaires - Tynes, T.; Aagestad, C.; Thorsen, S.V.; Andersen, L.L.; Perkio-Makela, M.; García, F.J.P.; Blanco, L.G.; Vermeylen, G.; Parent-Thirion, A.; Hooftman, W.; Houtman, I.; Liebers, F.; et al. (BMC Public Health, 2017)