Viable inflationary models in a ghost-free Gauss–Bonnet theory of gravityShin’ichi Nojiri, S. D. Odintsov, V. K. Oikonomou, N. Chatzarakis and Tanmoy PaulEur. Phys. J. C, 79 7 (2019) 565DOI: https://doi.org/10.1140/epjc/s10052-019-7080-1