The following articles give a short and comprehensive overview of the RMIB part of the GERB ground segment.
The first paper has been presented during the EUMETSAT 2000 Meteorological Satellite Data user's Conference in Bologna, Italy, June 2000.

S. Dewitte, N. Clerbaux , L. Gonzalez, A. Hermans, A. Ipe, A. Joukoff, G. Sadowski (2000):
Generation of
GERB Unfiltered Radiances and Fluxes,
In Proc. 2000 EUMETSAT Meteorological Satellite Data Users’ Conf (pp. 29-72).
An update has been issued in 2008, to provide a full description of the Edition-1 processing:

S. Dewitte, L. Gonzalez, N. Clerbaux, A. Ipe, C. Bertrand, B. De Paepe (2008):
The Geostationary Earth Radiation Budget Edition 1 data processing algorithms,
Advances in Space Research,
41(11), 1906-1913.