by Ravoson, V., Ramani, A., Grammaticos, B.
Published in Physics letters. A (08.08.1994)

by Brouzet, R, Caboz, R, Rabenivo, J, Ravoson, V
Published in Journal of physics. A, Mathematical and general (07.05.1996)

by Caboz, R, Ravoson, V, Gavrilov, L
Published in Journal of physics. A, Mathematical and general (21.05.1991)

by Ramani, A., Grammaticos, B., Ravoson, V.
Published in Physics letters. A (03.04.1995)