Approximability of dense and sparse instances of minimum 2-connectivity, TSP and path problems.

Béla Csaba Marek Karpinski Piotr Krysta Approximability of dense and sparse instances of minimum 2-connectivity, TSP and path problems. 74-83 2002 SODA http://doi.acm.org/10.1145/545381.545390 db/conf/soda/soda2002.html#CsabaKK02