toms461, a Fortran77 code which implements ACM toms algorithm 461, which uses cubic splines to solve a class of functional differential equations.
The text of many ACM TOMS algorithms is available online through ACM: https://www.acm.org/pubs/calgo or NETLIB: https://www.netlib.org/toms/index.html.
The information on this web page is distributed under the MIT license.
toms461 is available in a Fortran77 version.