Bhaskar DasGupta Tao Jiang Sampath Kannan Ming Li Elizabeth Sweedyk On the Complexity and Approximation of Syntenic Distance. 59-82 1998 88 Discrete Applied Mathematics 1-3 http://dx.doi.org/10.1016/S0166-218X(98)00066-3 db/journals/dam/dam88.html#DasguptaJKLS98