An investigation into random lasing from thin film on a sandpaper substrateZhi Ren, Ping Wang, Kun Ge, Yang liu, Guiyin Zhang, Zongli Sun and Songtao LiEur. Phys. J. D, 74 3 (2020) 53DOI: https://doi.org/10.1140/epjd/e2020-100484-0