by Robinson, I.K., Pitney, J.A., Libbert, J.L., Vartanyants, I.A.
Published in Physica. B, Condensed matter (01.06.1998)

by J.L. LIBBERT, R.J. FALSTER
Year of Publication 29.09.2004

by Libbert, J.L., Kelton, K.F., Gibbons, P.C., Goldman, A.I.
Published in Journal of non-crystalline solids (01.02.1993)

by Libbert, JL, Kelton, KF, Goldman, AI, Yelon, WB
Published in Physical review. B, Condensed matter (01.05.1994)