@booklet {son1999high,
	title = {High efficiency compact Cybagfilter},
	year = {1999},
	note = {US Patent 5,961,675},
	author = {Son, Jae-ik and Park, Young-Ok and Koo, Cheol-Oh and Lim, Jeong-hwan and Kim, Hong-Yong and Kim, Sang-Do and Chun, Tae-hee and Kwon, Hyock-Ju}
}
