1. V. M. Bondarenko, Representation of Gelfand Graphs [in Ukrainian], Institute of Mathematics, National Academy of Sciences of Ukraine, Kyiv (2005).
2. Z. I. Borevich, “On the factorization of matrices over the rings of principal ideals,” in: Abstr. of the 3rd All-Union Symp. on the Theory of Rings, Algebras, and Modules [in Russian], Tartu University, Tartu (1976), p. 19.
3. L. N. Vasershtein, "Stable rank of rings and dimensionality of topological spaces," Funkts. Anal. Prilozh., 5, No. 2, 17-27 (1971)
4. English translation: Funct. Anal. Appl., 5, No. 2, 102-110 (1971).
5. F. R. Gantmacher, The Theory of Matrices, Chelsea, New York (1959); http://science.sciencemag.org/content/131/3408/1216.2.