Planck Collaboration, Ade, P. A. R., Aghanim, N., Armitage-Caplan, C., Arnaud, M., Ashdown, M., et al. (2014). Planck 2013 results - XXIV. Constraints on primordial non-Gaussianity. Astronomy & Astrophysics, 571: A24. doi:10.1051/0004-6361/201321554.