People involved at OAB: Gilli, Comastri.
This research is in collaboration with G. Hasinger (MPE-Garching).
A detailed and self-consistent
modeling of the cosmic X-ray background (XRB) based on the most
up-to-date X-ray luminosity functions (XLF) and evolution of AGN
was published by Gilli, Comastri & Hasinger (2007).
A web based tool for computing the contribution to the XRB spectrum and
the logN-logS in different bands for AGN in any redshift, luminosity or 
bin
was developed, tested and released to the community at the address:
http://www.bo.astro.it/~gilli/xrb.html;
http://www.bo.astro.it/~gilli/counts.html
(see also Fig. 18).
The tool was very well received and used by several colleagues in
scientific papers and in observational proposals.