*1:See also https://sumita-m.hatenadiary.com/entry/20131004/1380911282 https://sumita-m.hatenadiary.com/entry/20150731/1438350631 https://sumita-m.hatenadiary.com/entry/20170825/1503684323 https://sumita-m.hatenadiary.com/entry/2020/04/04/115344 https://sumita-m.hatenadiary.com/entry/2020/04/11/140205 https://sumita-m.hatenadiary.com/entry/2020/06/01/015954 https://sumita-m.hatenadiary.com/entry/2020/10/11/074633
