1. Holly Z. More than meets the eye: NASA scientists listen to data. NASA. 2 Sept. 2014.Available from: www.nasa.gov/content/goddard/more-than-meets-the-eye-nasa-scientists-listen-to-data/
2. World Health Organization. Mental Health of Older Adults. World Health Organization. www.who.int/mediacentre/factsheets/fs381/en/
3. Japan: Population by Age Group 2020 | Statistic. Statista. www.statista.com/statistics/612575/japan-population-age-group/
4. Bach-Y-Rita P, Kercel SW. Sensory substitution and the human-machine interface. Trends in Cognitive Sciences. 2003;7(12):541-546. DOI: 10.1016/j.tics.2003.10.013
5. Bai J et al. Smart guiding glasses for visually impaired people in indoor environment. IEEE Transactions on Consumer Electronics. 2017;63(3):258-266. DOI: 10.1109/tce.2017.014980