1. A review of health-related workplace productivity loss instruments Bookmark Author: Lofland, J. H., Pizzi, L., and Frick, K. D. Publication year: 2004 DOI:
2. Quality appraisal of generic self-reported instruments measuring health-related productivity changes: a systematic review Bookmark Author: Noben, C. Y., Evers, S. M., Nijhuis, F. J., and de Rijk, A. E. Publication year: 2014 DOI: 10.1186/1471-2458-14-115