TOMS494 is a FORTRAN77 library which approximates a time-dependent partial differential equation (PDE) in one spatial dimension.
The text of many ACM TOMS algorithms is available online through ACM: http://www.acm.org/pubs/calgo or NETLIB: http://www.netlib.org/toms/index.html.
TOMS494 is available in a FORTRAN77 version.
TOMS565,
a FORTRAN77 library which
approximates the solution of a system of time-dependent partial differential
equations over a 2D domain;
this library is commonly called PDETWO;
this is ACM TOMS algorithm 565;
You can go up one level to the FORTRAN77 source codes.