@article{leonel_pires_1998,  title={Dynamics of the classical two dimensional XY ferromagnet at low temperatures: a memory function approach},  volume={28},  ISSN={0103-9733},  url={https://doi.org/10.1590/S0103-97331998000400023},  DOI={10.1590/S0103-97331998000400023},  number={4},  journal={Brazilian Journal of Physics},  publisher={Sociedade Brasileira de Física},  author={Leonel, S.A. and Pires, A.S.T.},  year={1998},  month={Dec},  pages={481–486} }