PageHeader : Funkcialaj Ekvacioj, 28 (1985), 193?211 Title : Well-posedness in Gevrey Classes of the Cauchy Problems Title : for Some Second Order Weakly Hyperbolic Operators AuthorInfo : By AuthorInfo : Hitoshi URYU and Shigeharu ITOH AuthorInfo : (Senshu University and Waseda University, Japan) section : 1. Introduction section : 2. Plan of the proof of Theorem 1 section : 3. Every estimates in $L^{2}$ section : 4. Estimates of derivatives of $u$ section : 5. Estimates of remainder terms section : 6. Proof of Theorem 2 section : Appendix section : References