Huygens' principle on Petrov type N space-times V. Wünsch — 1994 Annales de l'I.H.P. Physique théorique
Moments and Huygens' principle for conformally invariant field equations in curved space-times V. Wünsch — 1994 Annales de l'I.H.P. Physique théorique
Contributions to polynomial conformal tensors R. Gerlach; V. Wünsch — 1999 Annales de l'I.H.P. Physique théorique