Ruy Luiz Milidiú Artur Alves Pessoa Eduardo Sany Laber Complexity of Makespan Minimization for Pipeline Transportation of Petroleum Products. 243-255 2002 conf/approx/2002 APPROX http://link.springer.de/link/service/series/0558/bibs/2462/24620243.htm db/conf/approx/approx2002.html#MilidiuPL02