@misc{oai:nipr.repo.nii.ac.jp:00010624,
 author = {Ratovsky K.G. and Oinats A.V. and Nishitani N.},
 month = {Dec},
 title = {Polar ionosphere variability from Norilsk ionosonde and SuperDARN Ekaterinburg and Hokkaido HF radars},
 year = {2014}
}