Vehicle routing with Optaplanner - Stack Overflow
https://stackoverflow.com/questions/22285252/vehicle-routing-with-optaplanner
graph theory - OptaPlanner VRP edge weights need to use actual GPS data instead of Euclidean distance - Stack Overflow
https://stackoverflow.com/questions/19410972/optaplanner-vrp-edge-weights-need-to-use-actual-gps-data-instead-of-euclidean-di