The traveling salesman problem: A Linear programming formulation
  In this paper, we present a polynomial-sized linear programming formulation of the Traveling Salesman Problem (TSP). The proposed linear program is a network flow-based model. Numerical implementation issues and results are discussed. (The exposition and proofs are much more detailed in an edition which I wrote in collaboration with Dr. M.H. Karwan in 2012-2014 . That edition is available at http://users.business.uconn.edu/mdiaby/P=NPProofPapers/tspPaper.pdf) 
Moustapha Diaby