Found inBnF Service coréen. — Confucian statecraft and Korean institutions : Yu Hyŏngwŏn and the late Chosŏn Choson Dynasty / James B. Palais, 2006. — National library of Korea - http://nl.go.kr (2007-01-12). — LC Authorities : Yu, Hyŏng-wŏn, 1622-1673 - http://authorities.loc.gov (2007-01-12)