Cole, A.J., C. Jordan, and D.F. Merriam. “FORTRAN II Program for Progressive Linear Fit of Surfaces on a Quadratic Base Using an IBM 1620 Computer”. Bulletin (Kansas Geological Survey) (January 1, 1967): 1–54. Accessed January 5, 2026. https://journals.ku.edu/kgsbulletin/article/view/23491.