1. Khanh, T. Q., Bodrogi, P., Trinh, Q., Winkler, H., [LED lighting Technology and perception], Wiley-VCH, Weinheim (2015).
2. Khan, M. N., [Understanding LED illumination], CRC Press, Taylor & Francis, Boca Raton, FL (2014).
3. Winston, R., Minano, J. C., Benitez, P., Welford, W. T., [Nonimaging optics], Elsevier Academic Press, Burlington, Mass. (2005).
4. Tailored freeform optical surfaces
5. Freeform LED lens for uniform illumination