A note on a two dimensional knapsack problem with unloading constraints Jefferson Luiz Moisés da Silveira, Eduardo Candido Xavier and Flávio Keidi Miyazawa RAIRO-Theor. Inf. Appl., 47 4 (2013) 315-324 Published online: 23 August 2013 DOI: 10.1051/ita/2013037