SokolovN. P. “On Multiplicative and Spectral Properties of Space Matrices With Non-Negative Elements”. Ukrains’kyi Matematychnyi Zhurnal 18, no. 4 (June 28, 1966): 72-78. Accessed July 27, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/8314.