REFERENCES

Biondi, B., Fomel, S., and Alkhalifah, T., 1997, ``focusing'' eikonal equation and global tomography: SEP-95, 61-76.

Biondi, B., 1990, Velocity analysis using beam stacks: Ph.D. thesis, Stanford University.

Claerbout, J., and Nichols, D., 1993, Preconditioning: SEP-79, 227-228.

Claerbout, J., 1997, Multidimensional recursive filters via a helix: SEP-95, 1-13.

Claerbout, J., 1998, Multidimensional recursive filters via a helix: SEP-97, 319-336.

Clapp, R. G., Fomel, S., and Claerbout, J., 1997, Solution steering with space-variant filters: SEP-95, 27-42.

Clapp, R. G., Sava, P., and Claerbout, J. F., 1998, Interval velocity estimation with a null-space: SEP-97, 147-156.

Etgen, J., Problems and prospects in interval velocity estimation:, Presented at the Stanford Exploration Project Annual Meeting, 1997.

Fomel, S., Clapp, R., and Claerbout, J., 1997, Missing data interpolation by recursive filter preconditioning: SEP-95, 15-25.

Phillips, W. S., and Fehler, M. C., 1991, Traveltime tomography: A comparison of popular methods: Geophysics, 56, no. 10, 1639-1649.

Rekdal, T., and Biondi, B., 1994, Ray methods in rough models: SEP-80, 67-84.

Tarantola, A., 1987, Inverse problem theory: Elsevier.

van Trier, J., 1990, Tomographic determination of structural velocities from depth migrated seismic data: SEP-66.