The Adaptive Transversal Equalizer for 90MBPS 64-QAM Radio Relay System. - Koji Aoki; Hiroshi Yamada; Koji Ikuta; Sadao Takenaka; Yoshimasa Daido (ICC (2), 1984)

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)