Determination of the up/down-quark mass within QCD sum rules in the scalar channelFang-Hui Yin, Wen-Ya Tian, Liang Tang and Zhi-Hui GuoEur. Phys. J. C, 81 9 (2021) 818DOI: https://doi.org/10.1140/epjc/s10052-021-09599-3