Second order nonpersistence of the sine Gordon breather under an exceptional perturbation Jochen Denzler — 1995 Annales de l'I.H.P. Analyse non linéaire
Nonlinear diffusion from a delocalized source : affine self-similarity, time reversal, & nonradial focusing geometries Jochen Denzler; Robert J. McCann — 2008 Annales de l'I.H.P. Analyse non linéaire