@article{articlede030d5e,
title   = {An eigenvalue problem for the biharmonic operator on Z2-symmetric regions},
author = {Pereira, Antônio Luiz and Pereira, Marcone Corrêa},
year = {2008},
doi = {10.1112/jlms/jdm122},
journal   = {Journal of the London Mathematical Society}
}