void comp_next ( int n, int k, int a[], int *more, int *h, int *t );
double hexahedron_unit_monomial_integral ( int expon[3] );
double hexahedron_unit_volume ( );
void hexahedron_witherden_rule ( int p, int n, double x[], double y[], 
  double z[], double w[] );
double *monomial_value ( int m, int n, int e[], double x[] );
void r8vec_copy ( int n, double a1[], double a2[] );
int rule_order ( int p );
void rule01 ( int n, double x[], double y[], double z[], double w[] );
void rule03 ( int n, double x[], double y[], double z[], double w[] );
void rule05 ( int n, double x[], double y[], double z[], double w[] );
void rule07 ( int n, double x[], double y[], double z[], double w[] );
void rule09 ( int n, double x[], double y[], double z[], double w[] );
void rule11 ( int n, double x[], double y[], double z[], double w[] );