A multi-commodity, capacitated pickup and delivery problem: The single and two-vehicle cases.

Harilaos N. Psaraftis A multi-commodity, capacitated pickup and delivery problem: The single and two-vehicle cases. 572-580 2011 215 European Journal of Operational Research 3 http://dx.doi.org/10.1016/j.ejor.2011.06.038 db/journals/eor/eor215.html#Psaraftis11