Note that a transshipment problem can be formulated as cost-minimizing Lp model, similar to the transportation model given in (6.6). The objective cost function can be expressed as the sum of the costs given in (6.8) and (6.10), and the constraints included supply constraints (6.7), demand constraints (6.9), and transshipment balance constraints (6.11). Thus, an Lp transshipment model can be constructed as: