参考文献:
NAM, Ghilsoo Choi, Kyung Il Kim, Hye Ran Seo, Seon Hee Kim, Yoon Jee Shin, Hee Sup Kim, Dong Jin Pae, Ae Nim Chung, Hye Jin Choo, Hyunah Rhim, Hyewhon Cho, Yong Seo Roh, Eun Joo Keum, Gyo Chang Choi, Kee Hyun Shin, Kye Jung Hahn, Hoh Gyu Cheong, Chan Seong Lee, Jae Kyun Nam, Kee Dal Kang, Yong Koo Kim, Youngsoo Park, Woong Seo Kim, Eunice Eun-Kyeong Kim, Key-Sun Chung, Hesson Shin, Dong Yun Song, Chi man Patent: US1/946 A1, 1 Location in patent: Page/Page column 1