@Misc{ FloLiYam20, author = { Floridia, Giuseppe and Li, Zhiyuan and Yamamoto, Masahiro }, title = { Well-posedness for the backward problems in time for general time-fractional diffusion equation }, journal = { }, year = { 2020 }, pages = { }, URL = { http://cvgmt.sns.it/paper/4720/ }, note = { cvgmt preprint} }