TTA Journal, vol. 183, pp. 78 - 81, May/June 2019 http://tta.or.kr/data/reporthosulist_view.jsp?kind_num=1&hosu=183 http://tta.or.kr/ebook/ecatalog.jsp?catimage=1&Dir=65&start=78 https://www.nl.go.kr/NL/search/printMarcPop.do?viewKey=731242459&viewType=AH7