Planck 2015 results. XV. Gravitational lensing

P.A.R. Ade, N. Aghanim, M. Arnaud, M. Ashdown, J. Aumont, C. Baccigalupi, A.J. Banday, R.B. Barreiro, J. G. Bartlett, N. Bartolo, Per Rex Christensen, Anne Mette Frejsel, Pavel Nasselski, Igor Dmitrievich Novikov, Hans Ulrik Nørgaard-Nielsen