Sharshekeev, O. Sh., M. Sagynbaeva, and A. S. Taukenova. “CLOSED FRIEDMANN MODEL IN A MODIFIED GRAVITATIONAL THEORY”. Recent Contributions to Physics 39, no. 4 (December 20, 2011): 70–75. Accessed September 20, 2026. https://bph.kaznu.kz/index.php/zhuzhu/article/view/164.