https://www.bunka.go.jp/seisaku/shukyohojin/pdf/93975301_01.pdf
https://www.nichibenren.or.jp/library/pdf/activity/human/consumer/reikanreport3.pdf
https://www.nichibenren.or.jp/library/pdf/activity/human/consumer/reikanreport2.pdf
https://www.nichibenren.or.jp/library/pdf/activity/human/consumer/reikanreport1.pdf
https://www.bunka.go.jp/seisaku/shukyohojin/pdf/93975301_01.pdf