Ade, P. A. R.; et al. (2014). "Planck 2013 results. XXIII. Isotropy and statistics of the CMB". Astronomy & Astrophysics. 571: A23. arXiv:1303.5083. doi:10.1051/0004-6361/201321534.
Ade, P. A. R.; et al. (2014). "Planck 2013 results. XXIII. Isotropy and statistics of the CMB". Astronomy & Astrophysics. 571: A23. arXiv:1303.5083. doi:10.1051/0004-6361/201321534.