@article{oai:rikkyo.repo.nii.ac.jp:00021391,
 author = {Sugiyama, Kennichi},
 journal = {Commentarii mathematici Universitatis Sancti Pauli, Rikkyo Daigaku sugaku zasshi},
 month = {Dec},
 note = {P(論文)},
 pages = {23--42},
 title = {A Tower of Ramanujan Graphs and a Reciprocity Law of Graph Zeta Functions},
 volume = {69},
 year = {2021}
}