This note summarizes the connection between winner determination problems (WDPs) in multi-unit combinatorial exchanges and generalized knapsack problems (KPs); see [2] for an extensive treatment. Taxonomies of sealed-bid auction WDPs and of KPs align precisely, i.e., the two classes of problems are identical. The relationship between KPs and WDPs has received remarkably little attention in E-commerce and multi-agent systems literature. However the WDP-KP connection is important because it allows us to leverage a vast body of Operations Research literature for developing and benchmarking WDP solvers. For low-dimensional multi-unit CA WDPs (i.e., few types of goods), extremely simple dynamic-programming algorithms are available whose time and memory requirements are linear (in the pseudo-polynomial sense) in three out of four natural measures of problem size.