Genus Two Surface and Quarter BPS Dyons: The Contour Prescription
  Following the suggestion of hep-th/0506249 and hep-th/0612011, we represent quarter BPS dyons in N=4 supersymmetric string theories as string network configuration and explore the role of genus two surfaces in determining the spectrum of such dyons. Our analysis leads to the correct contour prescription for integrating the partition function to determine the spectrum in different domains of the moduli space separated by the walls of marginal stability. 
Shamik Banerjee, Ashoke Sen, Yogesh K. Srivastava