The production of t (t) over bar, W + b (b) over bar and W+ c (c) over bar is studied in the forward region of proton-proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98 +/- 0.02 fb(-1). The Wbosons are reconstructed in the decays W -> lv, where l denotes muon or electron, while the b and cquarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions. (C) 2017 The Author. Published by Elsevier B.V. This is an open access article under the CC BY license.