1. PERM (Algorithm 6);BOOTHROYD J;Computer Bulletin,1965
2. Permutation of the elements of a vector (Algomthm 29);BOOTHROYD J.;and "Fast permutation of the elements of a vector (Algorithm 30)," Computer J.,1967
3. Permutations with repetitious (Algomthm 306);ATLEY P;Comm ACM 1O,1967
4. Permutahon (Algorithm 71);YOU R R;Comm. ACM,1961
5. A simplified loop-free algorithm for generating permutations