found: Work cat.: 2006571117: Kim Yŏng-im ŭi Kyŏnggi sipi-chapka, c2005:p. 15 (Chapka originally sung by professional singers, became popular in 19th century)
found: Song, B. Source readings in Korean music:p. 86 ("Miscellaneous Song" musically it indicates semi-art song between folk and art song) p. 129 (a type of folk song developed by professional folk singers)
found: Garland Ency. of World Music:p. 885 (Chapka are sung sitting down (hence an alternative name Chwachʻang "setting songs") usually with instrumental accompaniments)
