1. The propagation of nonlinear wave envelopes;Benney;J. Math. and Phys.,1967
2. Theory of the propagation of high power laser radiation in a nonlinear medium;Lugovoi;Soviet Phys. Uspekhi,1973
3. Exact theory of two dimensional self-focussing and one dimensional self-modulation of waves in non-linear media;Zakharov;Soviet Phys. JETP,1972
4. The nature of the self-focussing singularity;Zakharov;Soviet Phys. JETP,1976
5. Collapse in the n-dimensional Schrödinger equation-a parallel with Sundman's results in the n-body problem;Berkshire;Stud. Appl. Math.,1983