1. Chover, J., King, J. (1981). Personal communication.
2. Nicholson, W. L., Merckx, K. R. (1969). “Unfolding Particle Size Distributions”. Technometrics, 11, 707–724.
3. Wahba, G. (1977), “Practical approximate solutions to linear operator equations when the data are noisy,” SIAM J. Numer. Anal., 14, 4.
4. Wahba, G. (1978), “Improper priors, spline smoothing and the problem of guarding against model errors in regression”, J. Roy. Stat. Soc. Ser. B., 40, 3.
5. Wendelberger, J. (1981), “The computation of Laplacian smoothing splines with examples”, University of Wisconsin Statistics Department Technical Report #648.