Gain of regularity for equations of KdV type W. Craig; T. Kappeler; W. Strauss — 1992 Annales de l'I.H.P. Analyse non linéaire
Results on qualitative features of periodic solutions of KdV T. Kappeler; B. Schaad; P. Topalov Séminaire Laurent Schwartz — EDP et applications
Foliation of phase space for the cubic non-linear Schrödinger equation D. Bättig; B. Grébert; J. C. Guillot; T. Kappeler — 1993 Compositio Mathematica