[BioC] GCRMA Bayes theory question

[Anne Pohrt]

Hi,

I am trying to understand how exactly the gcrma software works, and working my way through the Wu/Irizarry paper "A Model Based Background  Adjustment for Oligonucleotide Expression Arrays" . 
My problem is in understanding the Bayes approach that is behind it. I am particularly interested in how the integrated functions look like. 
Could anyone point me towards a source of the functions or a source with more detail than the paper I mentioned above?

Any help would be very much appreciated,
Best regards,
Anne Pohrt