1. City of Sapporo website, Road heating, available from <http://www.city.sapporo.jp/kensetsu/doroiji/works/workshop/road_heating.html>, (2011), (in Japanese), (accessed on 28th January, 2016).
2. City of Sapporo website, Answers for the question about the competition on town planning for future Makomanai, available from <https://www.city.sapporo.jp/keikaku/kougai/makomanai/documents/compekaitou140703.pdf>, (2014a), (in Japanese), (accessed on 28th January, 2016).
3. City of Sapporo website, Statistics on City of Sapporo, available from <http://www.city.sapporo.jp/toukei/tokeisyo/13energy25.html>, (2014b), (in Japanese), (accessed on 28th January, 2016).
4. City of Sapporo web site, available from <http://www.city.sapporo.jp/toukei/jinko/juuki/juuki.html>, (2014c), (in Japanese), (accessed on 28th January, 2016).
5. Furumichi, N., Fujiwara, Y., Ochifuji, K. and Satoh, K., Study on the problems in the introduction of a wide area district heating system to cold-climate cities and the effects on environmental load control, Proceedings of Symposium on Global Environment, Vol. 6 (1998), pp. 129-134 (in Japanese).