Source: https://www.researchgate.net/profile/Thierry_Garaix/publication/228681695_ETUDE_ET_RESOLUTION_DU_PROBLEME_DE_TRANSPORT_A_LA_DEMANDE_AVEC_QUALITE_DE_SERVICE/links/00463513f58b2470d9000000/ETUDE-ET-RESOLUTION-DU-PROBLEME-DE-TRANSPORT-A-LA-DEMANDE-AVEC-QUALITE-DE-SERVICE.pdf