@book{29085,
	author = {Winston, Roland, ed.},
	title = {Nonimaging Optics and Efficient Illumination Systems IV},
	publisher = {SPIE},
	year = {2007},
	series = {Proceedings of SPIE; V. 6670},
	address = {Washington, USA},
	url = {https://www.spiedigitallibrary.org/conference-proceedings-of-spie/6670}
}