Dineykhan, M., S. A. Zhaugasheva, and N. Khabyl. “Leptonic and Radiative Decays of Mesons With Beauty and Charm in the Relativistic Hamiltonian Approach”. International Journal of Mathematics and Physics, vol. 4, no. 1, June 2013, pp. 88-101, https://ijmph.kaznu.kz/index.php/kaznu/article/view/54.