1. Charles, J., & Lounsbury, F. (1915). Engineering economics. New York: McGraw-Hill.
2. Cheung, S. L., Lam, T., Li, D., & Wong, S. L. (2009). An analysis of energy-efficient light fittings and lighting controls. Applied Energy, 87, 558–567.
3. Chiang, J. H. (2010). Rsmeans electrical cost data 2010. Kingston, MA: Reed Construction Data.
4. Chletsis, A., Pilavachi, P., & Nikolaidis, Y. (2009). Economic evaluation of energy saving measures in a common type of Greek building. Applied Energy, 86(12), 2550–2559. doi: 10.1016/j.apenergy.2009.04.029 .
5. Clinton, M. B. (2008). A fundamental study on current industrial lighting systems and analyses of retrofit options. MS thesis, The University of Alabama.