1. McAllister, D.F. and Roulier, J.A. (1981), An algorithm for computing a shape-preserving osculatory quadratic spline, ACM Trans Math Software 7, 331-347.
2. Passow, E., and Roulier, J.A. (1977), Monotone and convex spline interpolation. SIAM J Num Anal 14, 904-909.
3. Fritsch, F.N., and Carlson, R.E. (1980), Monotone piecewise cubic interpolation, SIAM J Num Anal 17, 238-246.
4. Gregory, J.A. (1986), Shape-preserving spline interpolation, Computer-Aided Design, 18(1),53-57.
5. Fritsch, F.N., and Butland, J. (1984), A method for constructing local monotone piece- wise cubic interpolants, SIAM J Sc Stat Comput 5, 303-304.