Seiberg-Witten curves for elliptic models
  Four-dimensional N=2 gauge theories may be obtained from configurations of D-branes in type IIA string theory. Unitary gauge theories with two-index representations, and orthogonal and symplectic gauge theories, are constructed from configurations containing orientifold planes. Models with two orientifold planes imply a compact dimension, and correspond to elliptic models. Lifting these configurations to M-theory allows one to derive the Seiberg-Witten curves for these gauge theories. We describe how the Seiberg-Witten curves, necessarily of infinite order, are obtained for these elliptic models. These curves are used to calculate the instanton expansion of the prepotential; we explicitly find the one-instanton prepotential for all the elliptic models considered. 
I. Ennes, C. Lozano, S. Naculich, H. Schnitzer