A New 4 GHz 90 Mbps Digital Radio System Using 64-QAM Modulation. - Sadao Takenaka; Yukio Takeda; Toshiaki Sakane; Hiroshi Nakamura; N. Toyonaga (ICC (2), 1984)

Multilevel QAM Modulation Techniques for Digital Microwave Radios. - Yoshimasa Daido; Sadao Takenaka; Eisuke Fukuda; Toshiaki Sakane; Hiroshi Nakamura (IEEE J. Sel. Areas Commun., 1987)