1. Grasgruber, Pavel (2021), personal correspondence, July.
2. Japanese government, Ministry of Health, Labor, and Welfare. National Nutrition Surveys, various issues.
3. Republic of Korea, Korea Centers for Disease Control and Prevention, Korea National Health and Nutritional Examination Survey, various issues.
4. Japanese government, Ministry of Education, School Health Examination Survey, various issues.
5. Republic of Korea, Department of Education, Center for Educational Statistics, Statistical Yearbook of Education, various issues.