Citation: Pocha, R.; Ni, B.; Johrendt, D.; Abd-Elmeguid, M.M. (2005). Crystal structures, electronic properties and pressure induced superconductivity of the tetrahedral cluster compounds Ga Nb4 S8, Ga Nb4 Se8 and Ga Ta4 Se8. Journal of the American Chemical Society, 127, pp. 8732-8740.