@article{oai:ynu.repo.nii.ac.jp:00008713,
 author = {Konno, Norio and Segawa, Etsuo},
 journal = {Yokohama Mathematical Journal},
 month = {},
 pages = {65--78},
 title = {On the entropy of decoherence matrix for quantum walks},
 volume = {58},
 year = {2012}
}