1. M.R. Douglas, Conformal field theory techniques in large N Yang-Mills theory, in New Developments in String Theory, Conformal Models and Topological Field Theory, Cargese 1993, hep-th/9311130.
2. Two-dimensional QCD is a string theory;Gross;Nucl. Phys.,1993
3. S. Cordes, G. Moore and S. Rangoolam, Large N 2D Yang-Mills theory and topological string theory, Commun. Math. Phys. hep-th/9402107; Lectures on 2-D Yang-Mills theory, equivalent cohomology and topological field theories, Proceedings of the Trieste Spring School and the Cargese Summer School 1994, hep-th/9411210; G. Moore, 2D Yang-Mills theory and topological field theory, ICM94, hep-th/9409044.
4. P. Horava, Topological strings and QCD in two dimensions, hep-th/9311156; Topological rigid string theory and two dimensional QCD, hep9507060.
5. See e.g. P. Ginsparg and G. Moore, Lectures on 2D gravity and 2D string theory, TASI 92 lectures, hep-th/9304011.