On differences of self-adjoint semigroups Jan A. Van Casteren (1996) Annales mathématiques Blaise Pascal
On the semi-classical approximation of the solution of the Heisenberg equation with spin Wataru Ichinose (1997) Annales de l'I.H.P. Physique théorique
On the singularities of the solution of the Cauchy problem for the operator with non uniform multiple characteristics Yûsaku Hamada, Gen Nakamura (1977) Annali della Scuola Normale Superiore di Pisa - Classe di Scienze