Gryshchuk, S. V. (2018). Сommutative сomplex algebras of the second rank with unity and some cases of plane orthotropy. I.
Ukrains’kyi Matematychnyi Zhurnal
,
70
(8), 1058-1071.
https://umj.imath.kiev.ua/index.php/umj/article/view/1617