Title: Bis-diazodized-benzidine, tʻanninsan mit tʻŭrippʻŭsin chʻŏchʻi chŏkhyŏlgu ka myŏnyŏkhakchŏk yonghyŏl panŭng e michʻinŭn yŏnghyang oe pu nonmun 4-pʻyŏn