1. A 2016 Declining Birthrate White Paper. http://www8.cao.go.jp/shoushi/shoushika/whitepaper/measures/english/w-2016/
2. Robotic Care Devices Portal. http://robotcare.jp/en/home/index.php?lang=en
3. Baig, M.M., Afifi, S., GholamHosseini, H., Mirza, F.: A systematic review of wearable sensors and IoT-based monitoring applications for older adults-a focus on ageing population and independent living. J. Med. Syst. 43(8), 1–11 (2019). https://doi.org/10.1007/s10916-019-1365-7
4. Cabinet Office, J.: Annual Report on the Ageing Society [Summary] FY2020, July 2020. https://www8.cao.go.jp/kourei/english/annualreport/2020/pdf/2020.pdf
5. Creswell, J.W., Poth, C.N.:: Qualitative Inquiry and Research Design: Choosing Among Five Approaches. Sage Publications, Thousand Oaks (2016)