Yeung, S. W. A. (2005). The feasibility of implementing [master's thesis, The University of Hong Kong]. Airiti Library. https://www.airitilibrary.com/Article/Detail?DocID=U0029-1812201200018146
Hernberg, S. (1999). Towards a New Millennium. Scandinavian Journal of Work, Environment & Health, 25(6), 465-469. https://www.airitilibrary.com/Article/Detail?DocID=03553140-199911-201011100022-201011100022-465-469