@article{JEMS_2009_11_2_a5,
     author = {Liviu I. Ignat and Enrique Zuazua},
     title = {Convergence of a two-grid algorithm for the control of the wave equation},
     journal = {Journal of the European Mathematical Society},
     pages = {351--391},
     publisher = {mathdoc},
     volume = {11},
     number = {2},
     year = {2009},
     doi = {10.4171/jems/153},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/jems/153/}
}