De Gids, W.F. and Jacobs, P (2006) ‘An investigation into the possible reduction in Environmental Tobacco Smoke (ETS) in the day-to-day operations of the hospitality industry’, Nederlandse Organisatie voor Toegepast-Natuurwetenschappelijk Onderzoek.
de Gids, W.F. and Jacobs, P (2006) ‘An investigation into the possible reduction in Environmental Tobacco Smoke (ETS) in the day-to-day operations of the hospitality industry’, Netherlands Organisation for Applied Scientific Research.