Reference:
              (1) This is the long period ( > 2.3 * 10^18 ) random number generator of
                  P. L'Ecuyer, Commun. ACM 31, 743 (1988), but with Bays-Durham shuffle
                  and "added safeguards" as proposed by
              (2) William H. Press and Saul A. Teukolsky,
                  "Portable Random Number Generators",
                  Computers in Phyics, Vol. 6, No. 5, Sep/Oct 1992, Algorithm "ran2"
              (3) This generator has been validated also by
                  G. Marsaglia and A. Zaman,
                  "Some portable very-long-period random number generators",
                  Computers in Physics, Vol. 8, No. 1, Jan/Feb 1994.
            
             Notes:
               -  William Press and Saul Teukolsky think that this is a "perfect"
                  random generator and will pay $1000 for the first one who convinces
                  them otherwise.