1. V. Červený, V. Pretlová: Applications of Smoothed Splines in the Computation of Ray Amplitudes of Seismic Body Waves. Publ. Inst. Geophys. Pol. Acad. Sci., A-4 (115), Warszawa—Lódž 1977, 187.
2. V. Červený, V. Pretlová: Computation of Ray Amplitudes of Seismic Body Waves in Vertically Inhomogeneous Media. Studia geoph. et geod., 21 (1977), 248.
3. N. B. Pivovarova, T. P. Puchnačeva: Сглаживание зкспериментальных данных локальными сплайн-функциями. Математические проблемы геофизики 6, Новосибирск 1975, 281.
4. M. J. D. Powell: Curve Fitting by Cubic Splines. Proc. I.M.A. Conference at Canterbury on Numerical Approximations of Functions and Data. J. G. Hayes-ed., Athlone Press, Univ. of London, 1970.
5. M. J. D. Powell: Curve Fitting by Cubic Splines. Prep. T. P. 307, Atomic Energy Research Establishment, Harwell, England 1977: Numerical Approximations to Functions and Data. J. G. Hayes-ed., 65.