Multi-object auctions are traditionally analyzed as if they were a number of simultaneous independent single object auctions. Such an approximation may be very crude if bidders have budget restrictions, capacity constraints, or, in general, have non-linear utility functions. This paper presents a very simple multi-object auction for which explicit equilibrium strategies can be calculated; these equilibrium strategies have several qualitative characteristics arising from the multi-object nature of the example and therefore not present in typical single object auctions.
Engelbrecht-Wiggans, Richard, "An Example of a Multi-Object Auction Game" (1978). Cowles Foundation Discussion Papers. 727.