@article{oai:tsukuba.repo.nii.ac.jp:00017634,
 author = {Maruyama, I. and Hirano, T. and 初貝, 安弘 and HATSUGAI, Yasuhiro},
 issue = {11},
 journal = {Physical review B},
 month = {Mar},
 title = {Topological identification of a spin-(1/2) two-leg ladder with four-spin ring exchange},
 volume = {79},
 year = {2009},
 yomi = {ハツガイ, ヤスヒロ}
}