@article{oai:tsukuba.repo.nii.ac.jp:00027539,
 author = {宮本, 定明 and Miyamoto, Sadaaki},
 issue = {1},
 journal = {Annals of operations research},
 month = {May},
 pages = {221--236},
 title = {Different generalizations of bags},
 volume = {195},
 year = {2012}
}