<a href="https://arxiv.org/abs/1611.08003">The Breakdown of String Perturbation Theory for Many External Particles</a>

Citation:
Ghosh, Sudip, and Suvrat Raju. "The Breakdown of String Perturbation Theory for Many External Particles." Phys. Rev. Lett 118, no. 13 (2016): 131602.