THz electrodynamics of mixed-valent YbAl and LuAl thin filmsD. Barbalas, S. Chatterjee, D. G. Schlom, K. M. Shen and N. P. ArmitageEur. Phys. J. B, 94 9 (2021) 186DOI: https://doi.org/10.1140/epjb/s10051-021-00191-y