\begin{thebibliography}{KKG19}

\bibitem[AKS15]{AnKS15}
Hyung{-}Chan An, Robert~D. Kleinberg, and David~B. Shmoys.
\newblock Improving christofides' algorithm for the s-t path {TSP}.
\newblock {\em J. {ACM}}, 62(5):34:1--34:28, 2015.

\bibitem[Chr76]{Christofides76}
Nicos Christofides.
\newblock Worst-case analysis of a new algorithm for the travelling salesman
  problem.
\newblock {\em Technical Report 388, Graduate School of Industrial
  Adminstration, Carnegie-Mellon University, Pittsburgh, PA}, 1976.

\bibitem[KKG19]{KarlinKO19}
Anna Karlin, Nathan Klein, and Shayan~Oveis Gharan.
\newblock An improved approximation algorithm for {TSP} in the half integral
  case.
\newblock {\em CoRR}, abs/1908.00227, 2019.

\end{thebibliography}