CICOGNANI, Massimo; HIROSAWA, Fumihiko. On the Gevrey well-posedness for second order strictly hyperbolic Cauchy problems under the influence of the regularity of the coefficients. Mathematica Scandinavica, Berkeley, CA, United States, v. 102, n. 2, p. 283–304, 2008. DOI: 10.7146/math.scand.a-15063. Disponível em: https://journals.msp.org/mscand/article/view/634. Acesso em: 24 jul. 2026.