Heavy quark vacuum polarization: first two moments of the contribution K. G. Chetyrkin, J. H. Kühn, P. Mastrolia and C. Sturm Eur. Phys. J. C, 40 3 (2005) 361-366 Published online: 15 April 2005 DOI: 10.1140/epjc/s2005-02151-y