@incollection{JEDP_1998____A15_0, author = {Zelditch, Steve}, title = {Normal form of the wave group and inverse spectral theory}, booktitle = {}, series = {Journ\'ees \'equations aux d\'eriv\'ees partielles}, eid = {15}, pages = {1--18}, publisher = {Universit\'e de Nantes}, year = {1998}, mrnumber = {99h:58197}, zbl = {01808724}, language = {en}, url = {http://www.numdam.org/item/JEDP_1998____A15_0/} }