1. Statistical Office. 2019 population and housing census. 2020. Available from: https://eiec.kdi.re.kr/policy/materialView.do?num=204403&topic=. [Last accessed on 2020 Aug 28].
2. Lee SH Are you looking at the aging problem correctly? KERI Col 2013;4:1-3.
3. Kang KH, Kim KH An integrative study on the subjective happiness by eating foods in the elderly: Focus group interview. J Korea Acad Ind Coop Soc 2018;20:75-82.
4. Kwon SM The relation between desire and happiness from the viewpoint of psychology. Chul Hak Sa Sang: J Philos Ideas 2010;36:121-52.
5. Yang SC The effects of COVID-19 pandemic on real estate market. J Appraisal Stud 2020;19:5-28.