@article{10_4171_dm_168,
     author = {A. Ancona and B. Helffer and T. Hoffmann-Ostenhof},
     title = {Nodal domain theorems \`a la {Courant}},
     journal = {Documenta mathematica},
     pages = {283--299},
     year = {2004},
     volume = {9},
     doi = {10.4171/dm/168},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/dm/168/}
}