@article{oai:sit.repo.nii.ac.jp:00000504,
 author = {OKANO, Takeshi},
 issue = {9},
 journal = {Contexture : 教養紀要, Liberal arts bulletin of Saitama Institute of Technology},
 month = {Mar},
 pages = {55--59},
 title = {On the Irrationality of Σ^∞__<k=0> 1/((4k+1)^2)},
 year = {1992}
}