Fast calculation of HELAS amplitudes using graphics processing unit (GPU) K. Hagiwara, J. Kanzaki, N. Okamura, D. Rainwater and T. Stelzer Eur. Phys. J. C, 66 3-4 (2010) 477-492 Published online: 10 March 2010 DOI: 10.1140/epjc/s10052-010-1276-8