by Leemann, C., Skove, M.J., Stillwell, E.P.
Published in Solid state communications (01.07.1980)

by Davis, J.H., Skove, M.J., Stillwell, E.P.
Published in Solid state communications (01.01.1966)

by Cook, J.W., Skove, M.J., Stillwell, E.P., Thompson, R.S.
Published in Physics letters. A (01.01.1970)