@article{JSFS_1969__110__174_0,
     author = {Perquel, J.-J.},
     title = {Le co\^ut d'opportunit\'e},
     journal = {Journal de la Soci\'et\'e de statistique de Paris},
     pages = {174--183},
     publisher = {Soci\'et\'e de statistique de Paris},
     volume = {110},
     year = {1969},
     language = {fr},
     url = {http://www.numdam.org/item/JSFS_1969__110__174_0/}
}