Observation of focusing of 400 GeV/c proton beam with the help of bent crystals - Scandale, W; Arduini, G; Butcher, M; Cerutti, F; Gilardoni, S; Lechner, A; Losito, R; Masi, A; Metral, E; Mirarchi, D; Montesano, S; Redaelli, S; et al. (PHYSICS LETTERS B, 2014)