1. White paper on land, infrastructure, transportand tourism in japan (in Japanese);MLIT,2012
2. Policy of sewer management (in Japanese);MHLW,2019
3. Statistics of sewer maintenance (in Japanese);MLIT,2021
4. Influence of location of subsurface structures on development of underground cavities induced by internal erosion;Sato;Soils Found.,2015
5. Giant sinkhole in Japan repaired in a matter of days;McKirdy,2016