http://www.seas.gwu.edu/~simhaweb/champalg/tsp/tsp.html
http://davidsjohnson.net/papers/TSPchapter.pdf
http://people.idsia.ch/~luca/acs-bio97.pdf

@book{cook2014pursuit,
  title={In Pursuit of the Traveling Salesman: Mathematics at the Limits of Computation},
  author={Cook, W.J.},
  isbn={9780691163529},
  lccn={2011030626},
  year={2014},
  publisher={Princeton University Press}
}
