Hiroyuki Takeya, Humihiko.Takei, Yoji.Koike, Tetsuo.Fukase, Toetsu.Shishido.Naoki.Toyota, Yasuhiko.Syono, Humihiko Takei, Yoji Koike, Tetsuo Fukase, Toetsu Shishido, Naoki Toyota, Yasuhiko Syono.
Japanese Journal of Applied Physics 25 [Part 1, No. 12] 1954-1955. 1986.