@article{oai:soar-ir.repo.nii.ac.jp:00018387, author = {Endou, Noboru and Okazaki, Hiroyuki and Shidama, Yasunari}, issue = {3}, journal = {Formalized Mathematics}, month = {Oct}, note = {Article, Formalized Mathematics. 21(3): 163-170 (2013)}, pages = {163--170}, title = {Double Sequences and Limits}, volume = {21}, year = {2013} }