TOMS644 is a FORTRAN77 library which evaluates Bessel functions of complex argument and nonnegative real order.
TOMS644 is available in a FORTRAN77 version.
MACHINE, a FORTRAN77 library which stores the appropriate values of machine constants for a given machine.
SLATEC, a FORTRAN90 library which collects together a number of standard numerical libraries.
SPECFUN, a FORTRAN77 library which computes special functions, including Bessel I, J, K and Y functions, and the Dawson, E1, EI, Erf, Gamma, Psi/Digamma functions.
TOMS597, a FORTRAN77 library which can evaluate Bessel I functions of real (non integer) order, This is a version of ACM TOMS Algorithm 597;
TOMS715, a FORTRAN77 library which evaluates special functions, including the Bessel I, J, K, and Y functions of order 0, of order 1, and of any real order, Dawson's integral, the error function, exponential integrals, the gamma function, the normal distribution function, the psi function. This is a version of ACM TOMS algorithm 715.
You can go up one level to the FORTRAN77 source codes.