Heavy-quark mass dependence in global PDF analyses and 3- and 4-flavour parton distributions A.D. Martin, W.J. Stirling, R.S. Thorne and G. Watt Eur. Phys. J. C, 70 1-2 (2010) 51-72 Published online: 19 October 2010 DOI: 10.1140/epjc/s10052-010-1462-8