International Federation of Operation Research Societies., International Conference of Operational Research, & Brans, J. (1981). Operational research '81: Proceedings of the ninth IFORS International Conference on Operational Research, Hamburg, Germany, July 20-24, 1981 = Actes de la neuvieme IFORS Confιrence internationale de recherche operationnelle, Hamburg, Germany, juillet 20-24, 1981. Amsterdam: North-Holland Pub. Co..
Παραπομπή Chicago StyleInternational Federation of Operation Research Societies., International Conference of Operational Research, and J.P Brans. Operational Research '81: Proceedings of the Ninth IFORS International Conference On Operational Research, Hamburg, Germany, July 20-24, 1981 = Actes De La Neuvieme IFORS Confιrence Internationale De Recherche Operationnelle, Hamburg, Germany, Juillet 20-24, 1981. Amsterdam: North-Holland Pub. Co., 1981.
Παραπομπή MLAInternational Federation of Operation Research Societies., International Conference of Operational Research, and J.P Brans. Operational Research '81: Proceedings of the Ninth IFORS International Conference On Operational Research, Hamburg, Germany, July 20-24, 1981 = Actes De La Neuvieme IFORS Confιrence Internationale De Recherche Operationnelle, Hamburg, Germany, Juillet 20-24, 1981. Amsterdam: North-Holland Pub. Co., 1981.