1. N. Berkovits and O. Chandía, Massive superstring vertex operator in D = 10 superspace, JHEP 08 (2002) 040 [ hep-th/0204121 ] [ INSPIRE ].
2. M.B. Green, J.H. Schwarz and E. Witten, Superstring Theory, Volume 1, Cambridge University Press (1987).
3. N. Berkovits, Super Poincaré covariant quantization of the superstring, JHEP 04 (2000) 018 [ hep-th/0001035 ] [ INSPIRE ].
4. N. Berkovits, Pure spinor formalism as an N = 2 topological string, JHEP 10 (2005) 089 [ hep-th/0509120 ] [ INSPIRE ].
5. N. Berkovits, ICTP lectures on covariant quantization of the superstring, ICTP Lect. Notes Ser. 13 (2003) 57 [ hep-th/0209059 ] [ INSPIRE ].