Motlagh, A. N., Moslehian, M. S., & Khosravi, M. (2008). Vanishing of the first $(\sigma, \tau)$-cohomology group of triangular Banach algebras. Methods of Functional Analysis and Topology, 14(4), 351-360. https://zen.imath.kiev.ua/index.php/mfat/article/view/398