G. Delgado, P. Grima-Gallardo, and M. Quintero, Synthesis and crystal structure of three new quaternary compounds in the system (Cu-III-Se$_2$)$_{1-x}$ZnSe$_x$ (III = Al, Ga, In), formed by Zn incorporation in Cu-III-Se$_2$ chalcopyrites, Rev. Mex. Fís. 62, (2016).