Design and Performances of a 200 Mbit/s 16 QAM Digital Radio System. - Izumi Horikawa; Takehiro Murase; Yoichi Saito (IEEE Trans. Commun., 1979)

Characteristics of a High Capacity 16 QAM Digital Radio System in Multipath Fading. - Shozo Komaki; Izumi Horikawa; Kozo Morita; Yoshiharu Okamoto (IEEE Trans. Commun., 1979)

16 QAM Carrier Recovery PLL for Service-Channel Transmission Using FSK Additional Modulation. - Yoichi Saito; Izumi Horikawa; Heiichi Yamamoto (IEEE Trans. Commun., 1982)