Study of B c → D π in the perturbative QCD approach Jian-Feng Cheng, Dong-Sheng Du and Cai-Dian Lü Eur. Phys. J. C, 45 3 (2006) 711-720 Published online: 22 December 2005 DOI: 10.1140/epjc/s2005-02453-0