Charles,

All of the multi-particle vertex routines written by John McNabb are located in the CVS repository at packages/vertex. The c code is pretty well documented. I have slightly modified versions of the code that I use that are in FORTRAN that I have attached to this email. Details are given in McNabb's thesis. You can find this document online at: http://www.jlab.org/Hall-B/general/clas_thesis.html. Hope this is of some help to you.

Regards, Daniel