Direct calculation of the K-matrix for pion electro-production in the delta channel P. Alberto, L. Amoreira, M. Fiolhais, B. Golli and S. Širca Eur. Phys. J. A, 26 1 (2005) 99-106 Published online: 26 October 2005 DOI: 10.1140/epja/i2005-10160-9