@book{29975,
	author = {van Renesse, Rudolf, ed.},
	title = {Optical Security and Counterfeit Deterrence Techniques IV},
	publisher = {SPIE},
	year = {2002},
	series = {Proceedings of SPIE; V. 4677},
	address = {Washington, USA},
	url = {https://www.spiedigitallibrary.org/conference-proceedings-of-spie/4677}
}