1. E. Witten, Perturbative gauge theory as a string theory in twistor space, Commun. Math. Phys. 252 (2004) 189 [ hep-th/0312171 ] [ INSPIRE ].
2. R. Roiban, M. Spradlin and A. Volovich, On the tree level S matrix of Yang-Mills theory, Phys. Rev. D 70 (2004) 026009 [ hep-th/0403190 ] [ INSPIRE ].
3. F. Cachazo and Y. Geyer, A ’Twistor String’ Inspired Formula For Tree-Level Scattering Amplitudes in N = 8 SUGRA, arXiv:1206.6511 [ INSPIRE ].
4. F. Cachazo and D. Skinner, Gravity from Rational Curves in Twistor Space, Phys. Rev. Lett. 110 (2013) 161301 [ arXiv:1207.0741 ] [ INSPIRE ].
5. F. Cachazo, S. He and E.Y. Yuan, Scattering of Massless Particles in Arbitrary Dimension, arXiv:1307.2199 [ INSPIRE ].