AbstractGiven a set of sources with known capacities and a set of users with known demands for a product, the objective is to minimize the cost of assigning the users to the sources. The restrictions are that each user's demand is satisfied by exactly one of the sources, and that the total amount assigned to each source does not exceed its capacity. A fixed-charge version of this problem is formulated as a set partitioning problem and solved by a column-generating branch and bound procedure. Computational results are given.