Aleksi Julku, Grazia Salerno, and Päivi Törmä, Superfluidity of flat band Bose–Einstein condensates revisited, Low Temp. Phys. 49, 701–713, (2023) [Fiz. Nyzk. Temp. 49, 770–784, (2023)] DOI: https://doi.org/10.1063/10.0019426.