@article{PIM_1981_N_S_30_44_a8,
     author = {I. Jo\'o and L. L. Stach\'o},
     title = {An {Upper} {Estimation} for the {Eigenfrequences} of {Vibrating} {Liapunoff} {Bodies} (first {Boundary} {Value} {Problem)}},
     journal = {Publications de l'Institut Math\'ematique},
     pages = {59 },
     publisher = {mathdoc},
     volume = {_N_S_30},
     number = {44},
     year = {1981},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PIM_1981_N_S_30_44_a8/}
}