@article{PORMA_2001__58_1_49320,
     author = {Micu, S. and Zuazua, E.},
     title = {On the lack of null-controllability of the heat equation on the half space.},
     journal = {Portugaliae mathematica},
     pages = {1--24},
     publisher = {mathdoc},
     volume = {58},
     number = {1},
     year = {2001},
     zbl = {0991.35010},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_2001__58_1_49320/}
}