The first item is the principal reference for the RSPLINE program.
Schiess, James R.; and Kerr, Patricia A.:
Rational-Spline Approximation With Automatic Tension Adjustment.
NASA Technical Paper 2366, October 1984.
Hauck, Walter W., Jr.:
Foundations for Estimation by
the Method of Least Squares.
Spec. Rep. No. 340,
Smithsonian Astrophysical Observatory, Dec. 27, 1971.
(Available as
NASA Contractor Report 125549.)
Ahlberg, J. H.; Nilson, E. N.; and Walsh, J. L.:
The Theory of Splines and Their Applications.
Academic Press, Inc., c.1967.
Prenter, P. M.:
Splines and Variational Methods.
John Wiley & Sons, Inc., c.1975.
Cline, A. K.:
Scalar- and Planar-Valued Curve Fitting
Using Splines Under Tension.
Communications of the ACM,
vol. 17, no. 4, Apr. 1974, pp. 218-220.
Spath, Helmuth (W. D. Hoskins and H. W. Sager, transl.):
Spline Algorithms for Curves and Surfaces.
Utilitas Mathematica Pub. Inc., 1974.
Frost, Charles E.; and Kinzel, Gary L.:
An Automatic Adjustment Procedure for Rational Splines.
Computing and Graphics, vol. 6, no. 4, 1982, pp. 171-176.
Reinsch, C. H.: Smoothing by Spline Functions.
Numerical Mathematics, vol. 10, no. 3, 1967, pp. 177-183.
Smith, Robert E., Jr.; Price, Joseph M.; and Howser, Lona M.:
A Smoothing Algorithm Using Cubic Spline Functions.
NASA Technical Note D-7397, 1974.
Brent, R. P.: An Algorithm With Guaranteed
Convergence for Finding a Zero of a Function.
Computer Journal, vol. 14, no. 4, Nov. 1971, pp. 422-425.
Knott, Gary D.:
Interpolating Cubic Splines.
Birkhäuser, 1999.
deBoor,Carl:
A Practical Guide to Splines.
Springer-Verlag, 1978.
Smith, P.J.:
FITLOS - A Fortran Program for Fitting Low Order Polynomial Splines
by the Method of Least Squares.
NASA Technical Note D-6401, 1971.
Brent, Richard P.:
Algorithms for Minimization without Derivatives.
Courier Dover Publications, 1973.