STEAM_NBS_INTERACT is an FORTRAN77 program which allows the user to query the original version of the NBS steam tables.
The user can specify temperature and pressure, or temperature and density, and the program will return the computed values of a variety of quantities.
STEAM_NBS_INTERACT is available in a FORTRAN77 version.
STEAM_INTERACT, a FORTRAN90 program which queries the NBS steam table package;
STEAM_NBS, a FORTRAN77 library which is based on the NBS steam table package;
TEST_VALUES a FORTRAN90 library which stores selected values of various mathematical, statistical and physical functions, including some of the steam table functions.
You can go up one level to the FORTRAN77 source codes.