double besseljzero ( int k );
double besselj1squared ( int k );
void glpairs ( size_t n, size_t k, double *theta, double *weight, double *x );
void glpairtabulated ( size_t l, size_t k, double *theta, double *weight, 
  double *x );
void glpair ( size_t n, size_t k, double *theta, double *weight, double *x );
double legendre_theta ( int l, int k );
double legendre_weight ( int l, int k );
void timestamp ( );