Valakh, M.Ya.; Litvinchuk, A.P.; Dzhagan, V.M.; Yukhymchuk, V.O.; Yaremko, A.M.; Romanyuk, Yu.A.; Guc, M.; Bodnar, I.V.; Perez-Rodriguez, A.; Zahn, D.R.T. "Fermi resonance in the phonon spectra of quaternary chalcogenides of the type Cu2ZnGeS4" Journal of Physics Condensed Matter 28, 6, pp. - 2016 DOI: 10.1088/0953-8984/28/6/065401