@book{31989,
	author = {Soskin, Marat, ed.},
	title = {Second International Conference on Singular Optics (Optical Vortices): Fundamentals and Applications},
	publisher = {SPIE},
	year = {2001},
	series = {Proceedings of SPIE; V. 4403},
	address = {Washington, USA},
	url = {https://www.spiedigitallibrary.org/conference-proceedings-of-spie/4403}
}