Haim Kaplan Moshe Lewenstein Nira Shafrir Maxim Sviridenko Approximation Algorithms for Asymmetric TSP by Decomposing Directed Regular Multigraphs. 56- 2003 conf/focs/2003 FOCS http://csdl.computer.org/comp/proceedings/focs/2003/2040/00/20400056abs.htm db/conf/focs/focs2003.html#KaplanLSS03