  The galaxy number density is a key quantity to compare theoretical
predictions to the observational data from current and future Large Scale
Structure surveys. The precision demanded by these Stage IV surveys requires
the use of second order cosmological perturbation theory. Based on the
independent calculation published previously, we present the result of the
comparison with the results of three other groups at leading order. Overall we
find that the differences between the different approaches lie mostly on the
definition of certain quantities, where the ambiguity of signs results in the
addition of extra terms at second order in perturbation theory.
