1. 1) European Foundation for the Improvement of Living and Working Conditions (2006) Fourth European Working Conditions Survey. http://www.eurofound.europa.eu/ewco/surveys/index.htm. Accessed May 1, 2008.
2. 2) Park J, Lee N (2006) First Korean Working Conditions Survey. Occupational Safety and Health Research Institute, Korea Occupational Safety and Health Agency (KOSHA), Incheon.