1. Statistics Korea, Private Education Expenditures Survey 2021, Statistics Korea, 2021.
2. J. S. Yoo, An Analysis of Educational Indicators and the Impact of Private Education in Public Education, KERI Insight 21-1, Korea Economic Research Institute, 2021.
3. OECD, Education at a Glance report 2021, OECD, 2021.
4. OECD, OECD Factbook 2006, OECD, 2006.
5. The change of the private tutoring expenditure by school level and subject