Alday, L., Gaiotto, D., Gukov, S., Tachikawaa, Y., & Verlinde, H. (2010). Loop and surface operators in N=2 gauge theory and Liouville modular geometry.

Alday, L., D. Gaiotto, S. Gukov, Y. Tachikawaa, and H. Verlinde. Loop and Surface Operators in N=2 Gauge Theory and Liouville Modular Geometry. 2010.

Alday, L., et al. Loop and Surface Operators in N=2 Gauge Theory and Liouville Modular Geometry. 2010.