@Article{DellRighSala06,
author = {M. Dell'Amico and G. Righini and Matteo Salani },
title = {A Branch-and-Price Approach to the Vehicle Routing Problem with Simultaneous Distribution and Collection},
journal = {Transportation Science},
volume = {40},
number = {2},
pages = {235-247},
doi = {10.1287/trsc.1050.0118},
year = {2006}
}