Inflationary perturbation spectra at next-to-leading slow-roll order in effective field theory of inflationGuang-Hua Ding, Jin Qiao, Qiang Wu, Tao Zhu and Anzhong WangEur. Phys. J. C, 79 11 (2019) 976DOI: https://doi.org/10.1140/epjc/s10052-019-7496-7