On the Source of the Dust Extinction in Type Ia Supernovae and the Discovery of Anomalously Strong Na I AbsorptionPhillips, M. M., Joshua D. Simon, Nidia Morrell, Christopher R. Burns, Nick L. J. Cox, Ryan J. Foley, Amanda I. Karakas, F. Patat, A. Sternberg, R. E. Williams, A. Gal-Yam, E. Y. Hsiao, D. C. Leonard, Sven E. Persson, Maximilian Stritzinger, I. B. Thompson, Abdo Campillay, Carlos Contreras, Gastón Folatelli, Wendy L. Freedman, Mario Hamuy, Miguel Roth, Gregory A. Shields, Nicholas B. Suntzeff, Laura Chomiuk, Inese I. Ivans, Barry F. Madore, B. E. Penprase, Daniel Perley, G. Pignata, G. Preston, and Alicia M. Soderberg. “On the Source of the Dust Extinction in Type Ia Supernovae and the Discovery of Anomalously Strong Na I Absorption.” The Astrophysical Journal 779, no. 1 (2013): article 38.