D. Yoshida and J. Quintin. Maximal extensions and singularities in inflationary spacetimes. Class. Quant. Grav. 35 (2018) no. 15, 155019.
[2]
D. Yoshida, J. Quintin, M. Yamaguchi and R. Brandenberger. Cosmological perturbations and stability of nonsingular cosmologies with limiting curvature. Phys. Rev. D 96 (2017) 4, 043502.
[3]
T. Kobayashi, M. Siino, M. Yamaguchi and D. Yoshida. New cosmological solutions in massive gravity. Phys. Rev. D 86 (2012) 6, 061505.