looking for guttman scaling algorithm

[min-woong sohn]

Hi, netlanders.

I am doing some research in which we want to compute guttman scale values
of some 70 variables.  I know that SAS has a procedure called "proc
guttman" but it allows me to include only 12 variables.  This is too
a restriction for us.  Thus, I am exploring the possibility of writing
a program using either c or perl that allows me to include more than
70 variables in computing the guttman scaling algorithm.  I'd like to
do it on my pc or on a unix computer.  If any of you have an algorithm
that computes guttman scale values for a large number of variables,
can you please share your algorithm with me?  If any of you have heard of
a book, a person, or a anonymous ftp site, or whatever, could you please
be kind enough to point me to the person, book, etc.  

Thanks a lot,

Min

P.S.  BTW, please e-mail me at soh3 at midway.uchicago.edu.