@article{leitão_siqueira_vieira jr._almeida_2019,  title={Analysis of the global second-order effects on irregular reinforced concrete structures using the natural period of vibration},  volume={12},  ISSN={1983-4195},  url={https://doi.org/10.1590/S1983-41952019000200012},  DOI={10.1590/S1983-41952019000200012},  number={2},  journal={Revista IBRACON de Estruturas e Materiais},  publisher={IBRACON - Instituto Brasileiro do Concreto},  author={LEITÃO, F. F. and SIQUEIRA, G. H. and VIEIRA JR., L. C. M. and ALMEIDA, S. J. C.},  year={2019},  month={Mar},  pages={408–428} }