@article{Genkina1992,
    author = "Genkina, E.A. and Mill', B.V.",
    title = "Crystal structures of sphens Na Sb Ge O5, Na Ta Ge O5 and Li Ta Si O5.",
    journal = "Kristallografiya",
    year = "1992",
    volume = "37",
    pages = "1424-1428",
    ASTM_id = "KRISAJ"
}

@article{Mill'1990,
    author = "Mill', B.V. and Belokoneva, E.L. and Butashin, A.V.",
    title = "Synthesis and crystal structure of compounds A+ M5+ Ge O5 (A= Li, Na; M= Nb, Ta, Sb) and Li Ta Si O5",
    journal = "Kristallografiya",
    year = "1990",
    volume = "35",
    pages = "316-323",
    ASTM_id = "KRISAJ"
}