TY  - JOUR
AU  - Lebeau, Gilles
TI  - The wave equation with oscillating density : observability at low frequency
JO  - ESAIM: Control, Optimisation and Calculus of Variations
PY  - 2000
SP  - 219
EP  - 258
VL  - 5
PB  - EDP-Sciences
UR  - http://www.numdam.org/item/COCV_2000__5__219_0/
LA  - en
ID  - COCV_2000__5__219_0
ER  -