@article{01108901, title = {Perturbation expansions for eigenvalues and eigenvectors for a rectangular membrane subject to a restorative force.}, journal = {Electronic Research Announcements of the American Mathematical Society [electronic only]}, volume = {3}, year = {1997}, pages = {72-77}, doi = {10.1090/S1079-6762-97-00027-9}, zbl = {0887.35113}, language = {en}, url = {http://dml.mathdoc.fr/item/01108901} }
McLaughlin, Joyce R.; Portnoy, Arturo. Perturbation expansions for eigenvalues and eigenvectors for a rectangular membrane subject to a restorative force.. Electronic Research Announcements of the American Mathematical Society [electronic only], Tome 3 (1997) pp. 72-77. doi : 10.1090/S1079-6762-97-00027-9. http://gdmltest.u-ga.fr/item/01108901/