@article{CRMATH_2008__346_11-12_629_0,
     author = {Ammar-Khodja, Farid and Geymonat, Giuseppe and M\"unch, Arnaud},
     title = {On the exact controllability of a system of mixed order with essential spectrum},
     journal = {Comptes Rendus. Math\'ematique},
     pages = {629--634},
     publisher = {Elsevier},
     volume = {346},
     number = {11-12},
     year = {2008},
     doi = {10.1016/j.crma.2008.04.009},
     language = {en},
     url = {http://www.numdam.org/articles/10.1016/j.crma.2008.04.009/}
}