Galinsky, D. V. “Representations of $*$-Algebras Generated by Orthogonal Projections Satisfying a Linear Relation”. Methods of Functional Analysis and Topology 4, no. 3 (September 25, 1998): 27–32. Accessed December 19, 2025. https://zen.imath.kiev.ua/index.php/mfat/article/view/64.