Use of alcohol and drugs by Norwegian employees: a pilot study using questionnaires and analysis of oral fluid. - Gjerde, Hallvard; Christophersen, Asbjørg S.; Moan, Inger S.; Yttredal, Borghild; Walsh, J. Michael; Normann, Per T.; Mørland, Jørg (Journal of Occupational Medicine & Toxicology, 2010)