- Alinhac , S. 1978 . A class of hyperbolic operators with double involutive characteristics of Fuchsian type . Comm. Partial Differential Equations , 3 : 877 – 905 .
- Chazarain , J. 1974 . Propagation des singularitds pour une classe d'operateurs a caracteiistiques multiples et rdsolubilite locale . Ann. Inst. Fourier (Grenoble) , 24 : 203 – 223 .
- Dencker , N. 1982 . On the propagation of polarization sets for systems of real principal type, . J. Funct. Anal. , 46 : 351 – 372 .
- Dencker , N. 1989 . The propagation of singularities for pseudo-differential operators with self-tangential characteristics, . Ark. Mat. , 27 : 65 – 88 .
- Hormander , L. 1979 . The Weyl calculus of. pseudo-differential operators . Comm. Pure Appl. Math. , 32 : 359 – 443 .
- Hormander , L. 1985 . The Analysis of Linear Partial Differential Operators I-IV," , Berlin : Springer Verlag .
- Ivrii , V. Ja. 1979 . Wave fronts of solutions of symmetric pseudodifferential systems . Sibirsk. Mat. Z. , 20 : 557 – 578 . (Russian, english translation in Sibirian Math. J. 20 (1979), 390-405)
- Ivrii , V. Ja. 1979 . Wave fronts of solutions of certain hyperbolic pseudodifferential equations, . Trudy Moskov. Mat. Obsc. , 39 : 83 – 112 . (Russian, english translation in Trans. Moscow Math. Soc. 1981:1, 87-119)
- Kumano-go , H. and Taniguchi , K. 1979 . Fourier integral operators of multiphase and the fundamental solution for a hyperbolic system, . Funkcial Ekvac. , 22 : 161 – 196 .
- Lascar , R. 1976 . Propagation des singularite's pour une classe d'opkrateurs pseudo-dtff6rentaels d caracte ra siiques de multiplicitd variable . C. R. Acad. Sci. Paris Skr. A , 283 : 341 – 343 .
- Melrose , R. B. and Uhlmann , G. A. 1979 . Microlocal structure of involutive conical refraction, . Duke Math. J . , 46 : 571 – 582 .
- Morimoto , y. 1979 . Fundamental solution for a hyperbolic equation with involutive characteristics of variable multiplicity, . Comm. Partial Differential Equations , 4 : 609 – 643 .
- Nosmas , j. c. 1980 . Parame'triz du probldme de Cauchy pour une classe de systdmes hyperboliques symetrzsables ci caractistiques involutives de multaplicite variable . Comm. Partial Differential Equations , 5 : 1 – 22 .
- Tose , n. 1987 . Propagation of Stngularities for MicrodifferentiaI Equations with Multiple Self-tangential Involutory Characteristics, . Proc. Japan Acad. , 63A : 339 – 341 .
- Uhlmann , G. A. 1977 . Pseudo-differential operators with involutive double characteristics . Comm. Partial Differential Equations , 2 : 713 – 779 .
- Uhlmann , G. A. 1979 . Parametrices for operators with multiple involutive characteristics . Comm. Partial Differential Equations , 4 : 739 – 767 .
- Wakabayashi , W. 1983 . Singularities of solutions of the Cauchy problems for operators with nearly constant coeficient hyperbolic principal part, . Comm. Partial Differential Equations , 8 : 347 – 406 .
- Wakabayash , S. 1984 . Singularities of solutions of the Cauchy problem for symmetric hyperbolic systems, . Comm. Partial Differential Equations , 9 : 1147 – 1177 .
Communications in Partial Differential Equations
Volume 17, 1992 - Issue 9-10