Refrence for non-overlapping method in FreeFem documentation

Hello,

I don’t know if I can ask this here, but I’m looking on how can I reference the method shown in here


https://doc.freefem.org/models/domain-decomposition.html
do I reference freefem’s documentation if that’s possible or is there some other reference, because I have used a modified version of the code provided here.
Thank you,
Benfanich.