Towards extraction of π + p and π + π + cross-sections from charge exchange processes at the LHC R.A. Ryutin, V.A. Petrov and A.E. Sobol Eur. Phys. J. C, 71 5 (2011) 1667 Published online: 27 May 2011 DOI: 10.1140/epjc/s10052-011-1667-5