Non-linear label-free imaging through a multimode graded index optical fibreAngel Cifuentes, Johanna Trägårdh, Tomáš Pikálek, Mojmír Šerý, Denis Akimov, Tobias Meyer, Jürgen Popp, Rodrigo Amezcua-Correa and Tomáš ČižmárEPJ Web Conf., 238 (2020) 04006DOI: https://doi.org/10.1051/epjconf/202023804006