  In the case of Gamma-Ray Bursts with measured redshift, we can calculate the
k-correction to get the fluence and energy that were actually produced in the
comoving system of the GRB. To achieve this we have to use well-fitted
parameters of a GRB spectrum, available in the GCN database. The output of the
calculations is the comoving isotropic energy E_iso, but this is not the
endpoint: this data can be useful for estimating the {\Omega}M parameter of the
Universe and for making a GRB Hubble diagram using Amati's relation.
