Dear John, I wish to reference the deformation toolbox, in particular the inversion and application of deformation fields to PET images. I had a look on the Mailbase archive and SPM webpages, but couldn't find which papers to cite. Is "Ashburner & Friston (1998) Nonlinear spatial normalization using basis functions", the best one to cite? Suggestions please? Cheers, Mark =============================== Dr. Mark Daglish Clinical Lecturer in Psychiatry University of Bristol