Yang-Mills Theory as an Illustration of the Covariant Quantization of   Superstrings
  We present a new approach to the quantization of the superstring. After a brief review of the classical Green-Schwarz formulation for the superstring and Berkovits' approach to its quantization based on pure spinors, we discuss our formulation without pure spinor constraints. In order to illustrate the ideas on which our work is based, we apply them to pure Yang-Mills theory. In the appendices, we include some background material for the Green-Schwarz and Berkovits formulations, in order that this presentation be self contained. 
P.A.Grassi (YITP, Stony Brook), G. Policastro (DAMPT, Cambridge), and   P. van Nieuwehuizen (YITP, Stony Brook)