@article{PORMA_1977__36_3-4_115323,
     author = {Zaman, F.D.},
     title = {Perturbation of a biharmonic eigenvalue problem},
     journal = {Portugaliae mathematica},
     pages = {271--278},
     publisher = {mathdoc},
     volume = {36},
     number = {3-4},
     year = {1977},
     mrnumber = {0597849},
     zbl = {0457.31004},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1977__36_3-4_115323/}
}