upward

IV+V+VI compounds

Vateva E, Terziyska B, Arsova D, Low-temperature specific heat and thermal conductivity of ternary chalcogenide glasses, J Optoelectronics Adv Mater 9, 1965 (2007)

S Sen, S Gaudio, B G Aitken, C E Lesher, Observation of a pressure-induced first-order polyamorphic transition in a chalcogenide glass at ambient temperature, PRL 97, 025504 (2006)

Bychkov E, Tsegelnik V, Vlasova Y, Pradel A, Ribes M, Percolation transition in Ag-doped germanium chalcogenide-based glasses: conductivity and silver diffusion results, JNCS 208, 1 (1996) – doubtful results