*1:See also https://sumita-m.hatenadiary.com/entry/20081028/1225205805 https://sumita-m.hatenadiary.com/entry/2020/03/02/011405 https://sumita-m.hatenadiary.com/entry/2020/08/05/102533 https://sumita-m.hatenadiary.com/entry/2020/11/14/164535 https://sumita-m.hatenadiary.com/entry/2021/03/03/010412 https://sumita-m.hatenadiary.com/entry/2021/03/21/084125 https://sumita-m.hatenadiary.com/entry/2021/03/25/072032 https://sumita-m.hatenadiary.com/entry/2021/03/28/211305
