[Gretl-users] Multiple Linear Regression

I would be very gratefull if somebody would be so nice to point out to me which file in the C source-code is responsible for multiple linear regression computation (the coefficients) and the ADF (Augmented Dickey-Fullet Test). I am completely lost in the source code and accompanying files. I am also only interested in using the static library part of gretl, is there some usefull documentation on this (I was somewhat unsuccessfull in my searches) regards, Martin ps.: I am new to gretl, but next to jmulti this looks really cool.