Monotonicity preserving bicubic interpolation: A progress report. - Fred N. Fritsch; Ralph E. Carlson (Comput. Aided Geom. Des., 1985)

A Note on Piecewise Monotonic Bivariate Interpolation. - Ralph E. Carlson; Fred N. Fritsch (Curves and Surfaces, 1991)

A Bivariate Interpolation Algorithm for Data that are Monotone in One Variable. - Ralph E. Carlson; Fred N. Fritsch (SIAM J. Sci. Comput., 1991)