Key points are not available for this paper at this time.
Dilin Liu, Gil-Soon Ahn, Kyung-Suk Baek, Nan-Ok Han, South Korean High School English Teachers' Code Switching: Questions and Challenges in the Drive for Maximal Use of English in Teaching, TESOL Quarterly, Vol. 38, No. 4 (Winter, 2004), pp. 605-638
Liu et al. (2004) studied this question.