I found a couple of algorithms (expressed in Fortran, but it should be easy to convert¹ them to Perl ;-)) on Netlib, specifically 403 and 448. The algortithms were published in ACM's Collected Algorithms and Transactions on Mathematical Software in the early 1970's; both CALGO and TOMS are refereed publications, so at least one person other than the author has vetted the code.

¹ I'll try to do that tonight.