@incollection{SB_1976-1977__19__19_0, author = {Duistermaat, J. J.}, title = {The light in the neighborhood of a caustic}, booktitle = {S\'eminaire Bourbaki : vol. 1976/77, expos\'es 489-506}, author = {Collectif}, series = {S\'eminaire Bourbaki}, note = {talk:490}, publisher = {Springer-Verlag}, number = {19}, year = {1978}, zbl = {0401.35063}, mrnumber = {521757}, language = {en}, url = {http://www.numdam.org/item/SB_1976-1977__19__19_0/} }