Ángel Felipe M. Teresa Ortuño Gregorio Tirado Using intermediate infeasible solutions to approach vehicle routing problems with precedence and loading constraints. 66-75 2011 211 Eur. J. Oper. Res. 1 https://doi.org/10.1016/j.ejor.2010.11.011 db/journals/eor/eor211.html#FelipeOT11