Hiroshi Akima. Algorithm 697: univariate interpolation that has the accuracy of a third-degree polynomial. ACM Transactions on Mathematical Software, 17(3):367, 1991. [doi]
@article{Akima91a,
title = {Algorithm 697: univariate interpolation that has the accuracy of a third-degree polynomial},
author = {Hiroshi Akima},
year = {1991},
doi = {10.1145/114697.116808},
url = {http://doi.acm.org/10.1145/114697.116808},
researchr = {https://researchr.org/publication/Akima91a},
cites = {0},
citedby = {0},
journal = {ACM Transactions on Mathematical Software},
volume = {17},
number = {3},
pages = {367},
}