Maguire, K., Sullivan, M., Pan, Y.-C., Gal-Yam, A., Hook, I. M., Howell, D. A., Nugent, P. E., Mazzali, P., Chotard, N., Clubb, K. I., Filippenko, A. V., Kasliwal, M. M., Kandrashoff, M. T., Poznanski, D., Saunders, C. M., Silverman, J. M., Walker, E., & Xu, D. (2014). Exploring the spectral diversity of low-redshift type Ia supernovae using the Palomar Transient Factory. Monthly Notices of the Royal Astronomical Society, 444(4), 3258-3274. doi:10.1093/mnras/stu1607.