Adam Kasperski Pawel Zielinski A 2-approximation algorithm for interval data minmax regret sequencing problems with the total flow time criterion. 343-344 2008 36 Oper. Res. Lett. 3 http://dx.doi.org/10.1016/j.orl.2007.11.004 db/journals/orl/orl36.html#KasperskiZ08