Inclusion of CM-fields and divisibility ofrelative class numbers Ryotaro Okazaki — 2000 Acta Arithmetica
Determination of all non-normal quartic CM-fields and of all non-abelian normal octic CM-fields with class number one Stéphane Louboutin; Ryotaro Okazaki — 1994 Acta Arithmetica
On the number of solutions of simultaneous Pell equations II Michael A. Bennett; Mihai Cipu; Maurice Mignotte; Ryotaro Okazaki — 2006 Acta Arithmetica