Geometric optics for the wave equation

• Constructive and destructive interferences in nonlinear hyperbolic equations.
  With Christophe Cheverry. Mém. Soc. Math. Fr. (N.S.) No. 174 (2022), vi+110 pp. [memoir|preprint]
• Focusing of Spherical Nonlinear Pulses in R¹⁺³, III. Sub and Supercritical cases.
  With Jeffrey Rauch. Tohoku Math. J. 56 (2004), no. 3, 393-410. [article|preprint]
• Focusing of Spherical Nonlinear Pulses in R¹⁺³, II. Nonlinear caustic.
  With Jeffrey Rauch. Rev. Mat. Iberoamericana 20 (2004), no. 3, 815-864. [article]
• Focusing of a pulse with arbitrary phase shift for a nonlinear wave equation.
  With David Lannes. Bull. Soc. Math. France 131 (2003), 289-306. [article]
• Focusing of Spherical Nonlinear Pulses in R¹⁺³.
  With Jeffrey Rauch. Proc. Amer. Math. Soc. 130 (2002), 791-804. [article]
• Comportements précisés près d'une caustique en optique géométrique non linéaire.
  Comm. in Partial Diff. Eq. 23 (1998), nos. 11-12, 1929-1967. [article]