Domanov, I. U. “On Cyclic and Invariant Subspaces of an Operator $J\otimes B$ in the Sobolev Spaces of Vector Functions”. Methods of Functional Analysis and Topology 5, no. 1 (March 25, 1999): 1–12. Accessed December 17, 2025. https://zen.imath.kiev.ua/index.php/mfat/article/view/78.