*2:See also https://sumita-m.hatenadiary.com/entry/20071213/1197559069 https://sumita-m.hatenadiary.com/entry/20080224/1203784028 https://sumita-m.hatenadiary.com/entry/20090712/1247372170 https://sumita-m.hatenadiary.com/entry/20110523/1306114247 https://sumita-m.hatenadiary.com/entry/2019/11/03/100641