Using spectral flux ratios to standardize SN Ia luminosities S. Bailey, G. Aldering, P. Antilogus, C. Aragon, C. Baltay, S. Bongard, C. Buton, M. Childress, N. Chotard, Y. Copin et al. (16 more) A&A, 500 2 (2009) L17-L20 Published online: 13 May 2009 DOI: 10.1051/0004-6361/200911973