Please do not forget to cite:

Langer, G.G., Cohen, S.X., Perrakis, A. & Lamzin, V.S. (2008) Automated macromolecular model building for X-ray crystallography using ARP/wARP version 7. Nature Protocols 3, 1171-1179.

CCP4 (1994) Collaborative Computational Project Number 4. The CCP4 suite: programs for protein crystallography. Acta Crystallogr. D50, 760-763.

Murshudov, G.N., Vagin, A.A. & Dodson, E.J. (1997) Refinement of macromolecular structures by the maximum-likelihood method. Acta Crystallogr. D53, 240-255.

Also, please visit the ARP-wARP site for additional ARP/wARP references.