Here is an example of proper credit for these Virgo data.

The simulations in this paper were carried out by the Virgo Supercomputing Consortium using computers based at Computing Centre of the Max-Planck Society in Garching and at insitute for Computational Cosmology. The data are publicly available at www.mpa-garching.mpg.de/NumCos

GIF2 simulation are detailed in paper "The subhalo population of LCDM haloes", by Liang Gao, Simon D.M. White, Adrian Jenkins, Felix Stoehr and Volker Springel, 2004, MNRAS, 355, 819 astro-ph/040458