Chen Liang, Kong Wei, B.J. Ye, H.M. Wen, X.Y. Zhou, and R.D. Han, Green’s function method to the ground state properties of a two-component Bose-Einstein condensate: Бозе-эйнштейновская конденсация, Low Temp. Phys. 37, (2011) [Fiz. Nizk. Temp. 37, 708-714, (2011)] DOI: https://doi.org/10.1063/1.3633685.