@article{GDZPPN00117682X,
title = {The Finite Element Method with Non-Uniform Mesh Sizes Applied to the Exterior Helmholtz Problem.},
journal = {Numerische Mathematik},
volume = {39},
year = {1982},
pages = {61-82},
zbl = {0445.65102},
url = {http://dml.mathdoc.fr/item/GDZPPN00117682X}
}
Goldstein, C.I. The Finite Element Method with Non-Uniform Mesh Sizes Applied to the Exterior Helmholtz Problem.. Numerische Mathematik, Tome 39 (1982) pp. 61-82. http://gdmltest.u-ga.fr/item/GDZPPN00117682X/