ОvsepyanK. H. “Type of Some Nuclear Subalgebras of the Toeplitz Algebra Generated by the inverse subsemigroups of a Bicyclic Semigroup”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 69, no. 11, Nov. 2017, pp. 1551-63, http://umj.imath.kiev.ua/index.php/umj/article/view/1802.