1. Abe, O. (2009): Current status and perspectives of education for sustainable development (ESD). Environmental Education, 19(2), 21-30.
2. Abe, O. (2012): What is education for sustainable development (ESD)?. in An Introduction to ESD (Jizoku Kano Na Kaihatsu No Tame No Kyoiku ESD Nyumon) edited by Sato, M. and Abe, O., Tsukuba-shobo, 9-23.*
3. Ando, T. (2012): About geopark. Toppazure (Rotary Club of Choshi-East), 1945, 2-4.*
4. Anonymous (2015a): UNESCO Global Geoparks. UNESCO.
http://www.unesco.org/new/en/natural-sciences/environment/earth-sciences/global-geoparks/ [Cited 2016/06/24].
5. Anonymous (2015b): What is Education for Sustainable Development?.
http://en.unesco.org/themes/education-sustainable-development/what-is-esd [Cited 2016/06/24].