Monetone B-spline Smoothing
This note is based on He, X., & Shi, P. (1998). Monotone B-Spline Smoothing. Journal of the American Statistical Association, 93(442), 643–650., and the reproduced simulations are based on the updated algorithm, Ng, P., & Maechler, M. (2007). A fast and efficient implementation of qualitatively constrained quantile smoothing splines. Statistical Modelling, 7(4), 315–328.
Basic of $B$-splines
This note is based on de Boor, C. (1978). A Practical Guide to Splines, Springer, New York.