looking for guttman scaling algorithm

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