@article{CRMATH_2005__341_11_707_0,
     author = {Musy, Fran\c{c}ois and Nicolas, Laurent and Perrussel, Ronan},
     title = {Gradient-prolongation commutativity and graph theory},
     journal = {Comptes Rendus. Math\'ematique},
     pages = {707--712},
     publisher = {Elsevier},
     volume = {341},
     number = {11},
     year = {2005},
     doi = {10.1016/j.crma.2005.09.037},
     language = {en},
     url = {http://www.numdam.org/articles/10.1016/j.crma.2005.09.037/}
}