1. Auberson, G., Mennessier, G. (1989): Commun. Math. Phys. 121, 49 Ciulli, S., Spearman, T.D. (1984): Nuovo Cimento 83A, 352
2. Ciulli, M., (1988): Ph.D. thesis, University of Dublin (unpublished)
3. Ciulli, M., Ciulli, S., Spearman, T.D. (1990): Festschrift for André Martin, Springer Tracts in Modern Physics (Springer, Berlin, Heidelberg, New York).
4. Sabatier, P.C. (1978): Applied Inverse Problems, Lecture Notes in Physics No. 85 (Springer,
5. Berlin, Heidelberg, New York)