http://1manken.hatenablog.com/entry/2016/04/29/220000
http://akiya123.hatenablog.com/entry/2016/04/29/233556
http://www.machikado-creative.jp/theory/26115/
https://nandemo-nobiru.com/285/
http://www.dhbr.net/articles/-/4156
http://diamond.jp/articles/-/90470
http://realestate-column.com/calculate-depreciation
http://news.yahoo.co.jp/pickup/6199448
https://note.mu/chuckberry/n/n6b7287369950