@book{33339,
	author = {Ursu, Ioan, ed.},
	title = {Trends in Quantum Electronics},
	publisher = {SPIE},
	year = {1989},
	series = {Proceedings of SPIE; V. 1033},
	address = {Washington, USA},
	url = {https://www.spiedigitallibrary.org/conference-proceedings-of-spie/1033}
}