Generating Beta Variates with Nonintegrel Shape Parameters
A new rejection method is described for generating
beta variates.  The method is compared with 
previously published methods both theoretically and through
computer timings.  It is suggested that the 
method has advantages in both speed and programming
simplicity over previous methods, especially for 
"difficult" combinations of parameter values.
CACM April, 1978
Cheng, R.C.H.
