Towards parton distributions with fitted charm af Groth-Merrild, P, Rottoli, L, Ball, R, Bertone, V, Carrazza, S, Del Debbio, L, Forte, S, Groth-Merrild, P, Guffanti, A, Hartland, P, Kassabov, Z, Latorre, I, Rojo, J, Rottoli, L, Ubiali, M