*1:See also https://sumita-m.hatenadiary.com/entry/20130328/1364434114
*2:See also https://sumita-m.hatenadiary.com/entry/20160901/1472698104 https://sumita-m.hatenadiary.com/entry/20160905/1473001573 https://sumita-m.hatenadiary.com/entry/2019/10/05/084846 https://sumita-m.hatenadiary.com/entry/2019/12/31/023348 https://sumita-m.hatenadiary.com/entry/2020/01/11/024638 https://sumita-m.hatenadiary.com/entry/2020/01/15/094009 https://sumita-m.hatenadiary.com/entry/2020/01/16/084538 https://sumita-m.hatenadiary.com/entry/2020/01/28/012431 https://sumita-m.hatenadiary.com/entry/2020/01/28/104902 https://sumita-m.hatenadiary.com/entry/2020/02/03/135611 https://sumita-m.hatenadiary.com/entry/2020/02/14/104928 https://sumita-m.hatenadiary.com/entry/2020/02/20/020721 https://sumita-m.hatenadiary.com/entry/2020/02/22/082607 https://sumita-m.hatenadiary.com/entry/2020/02/25/083641 https://sumita-m.hatenadiary.com/entry/2020/02/26/135922 https://sumita-m.hatenadiary.com/entry/2020/03/02/085921 https://sumita-m.hatenadiary.com/entry/2020/03/13/132015 https://sumita-m.hatenadiary.com/entry/2020/03/15/094840