Seifert, Ralf W.Thonemann, U. W.Hausman, W. H.2004-09-072004-09-072004-09-07200410.1016/S0377-2217(02)00754-3https://infoscience.epfl.ch/handle/20.500.14299/170108Optimal Procurement Strategies for Online Spot Marketstext::journal::journal article::research article