Ab initio study of new sp3 silicon and germanium allotropes predicted from the zeolite topologiesVladimir A. Saleev, Alexandra V. Shipilova, Davide M. Proserpio and Giuseppe FaddaEur. Phys. J. B, 90 8 (2017) 150DOI: https://doi.org/10.1140/epjb/e2017-80152-2