1. ARKIN, H. & COLTON, R. R., 1970.Statistical Methods.(Barnes and Noble, New York.)
2. BECKETT, R. & HURT, J., 1967.Numerical Calculations and Algorithms.(McGraw Hill, New York).
3. EVJEN, H. M., 1967. Outline of a system of refraction interpretation for monotonic increases of velocity with depth; inSeismic Refraction Prospecting(Soc. Expl. Geophys., Tulsa) pp. 290-294.
4. GREENHALGH, S. A., 1976. Seismic refraction studies in variable velocity media. M.Sc. Thesis, University of Sydney (unpublished).
5. GREVILLE, T. N., 1967.Theory and Applications of Spline Functions(Academic Press, New York).