Zlatko Koinov, Collective-mode dispersion of atomic Fermi gases in a honeycomb optical lattice: speed of sound of the attractive Kane–Mele–Hubbard model at half filling, Low Temp. Phys. 46, (2020) [Fiz. Nizk. Temp. 46, 613-621, (2020)] DOI: https://doi.org/10.1063/10.0001056.