@article{JEDP_1990____A20_0, author = {Klopp, Fr\'ed\'eric}, title = {Impuret\'es dans une structure p\'eriodique}, journal = {Journ\'ees \'equations aux d\'eriv\'ees partielles}, eid = {20}, publisher = {Ecole polytechnique}, year = {1990}, zbl = {0707.35125}, mrnumber = {91k:35184}, language = {fr}, url = {http://archive.numdam.org/item/JEDP_1990____A20_0/} }