MarkinM. V. “On Scalar-Type Spectral Operators and Carleman Ultradifferentiable <i>C</i><sub>0</Sub&gt;-Semigroups”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 60, no. 9, Sept. 2008, pp. 1215 -, https://umj.imath.kiev.ua/index.php/umj/article/view/3238.