@article{ERAAMS_1997_03_a9,
     author = {McLaughlin, Joyce and Portnoy, Arturo},
     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},
     pages = {72--77},
     publisher = {mathdoc},
     volume = {03},
     year = {1997},
     doi = {10.1090/S1079-6762-97-00027-9},
     url = {http://geodesic.mathdoc.fr/articles/10.1090/S1079-6762-97-00027-9/}
}