Nonlinear Partial Differential Equations and Applications : Proceedings of a Special Seminar Held at Indiana University 1976–1977 Euler equation and burger equation — Relation with turbulence Asymptotic behavior of a model in population genetics A minimax principle and applications to elliptic partial differential equations The existence of periodic water waves An application of the Nash moser theorem to a free boundary problem Singularities in non linear waves of Klein Gordon type Bifurcations of dynamical systems and nonlinear oscillations in engineering systems.