@article{oai:nagoya.repo.nii.ac.jp:00020112, author = {Matuura, Nobuo and Okada, Toshimi}, journal = {Proceedings of the Research Institute of Atmospherics, Nagoya University}, month = {Mar}, pages = {85--88}, title = {ACTIVITY REPORT : Group 2.1 Ionospheric Physics}, volume = {37}, year = {1990} }