Tulkin Rasulov, and Mubina Sharipova. “TWO AND THREE PARTICLE BRANCHES OF THE ESSENTIAL SPECTRUM OF A 3×3 OPERATOR MATRICES”. Spectrum Journal of Innovation, Reforms and Development 8 (October 29, 2022): 270–274. Accessed November 7, 2024. https://sjird.journalspark.org/index.php/sjird/article/view/299.