Calculation of HELAS amplitudes for QCD processes using graphics processing unit (GPU) K. Hagiwara, J. Kanzaki, N. Okamura, D. Rainwater and T. Stelzer Eur. Phys. J. C, 70 1-2 (2010) 513-524 Published online: 19 October 2010 DOI: 10.1140/epjc/s10052-010-1465-5