1. Diagonalisation des systèmes quasi-linéaires et hyperbolicité non stricte;Bruhat;J. Math. Pures et Appl.,1966
2. On the compatibility of relativistic wave equations for particles of higher spin in the presence of a gravitational field;Buchdahl;Nuovo Cim.,1958
3. The Bach equations are an exact set of spinor fields;Frauendiener;Twistor Newsletter,1993
4. On the symplectic structure of general relativity;Frauendiener,1992
5. An algebraic treatment of certain classes of spinor equations and an application to general relativity;Frauendiener,1993