1. P.A.R. Ade et al., (Planck Collaboration), Planck 2013 results. XXIII. Isotropy and Statistics of the CMB. arXiv:1303.5083 [astro-ph.CO]
2. C.L. Bennett et al., (WMAP Collaboration), Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Final Maps and Results. arXiv:1212.5225 [astro-ph.CO]
3. G. Hinshaw et al., (WMAP Collaboration), Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Parameter Results. arXiv:1212.5226 [astro-ph.CO]
4. M.A. Watanabe, S. Kanno, J. Soda, Inflationary Universe with Anisotropic Hair. Phys. Rev. Lett. 102, 191302 (2009). arXiv:0902.2833 [hep-th]
5. R. Emami, H. Firouzjahi, S.M. Sadegh Movahed, M. Zarei, Anisotropic inflation from charged scalar fields. JCAP 1102, 005 (2011). arXiv:1010.5495 [astro-ph.CO]