@article{article3d18f08b,
title   = {Symmetry and bifurcation to 2'PI'-periodic solutions of nonlinear second-order equations with 2'PI' / m-periodic forcings},
author = {Furkotter, M and Rodrigues, Hildebrando Munhoz},
year = {1991},
journal   = {Siam Journal on Mathematical Analysis}
}