@article{singer_2015,  title={Quatro notas sobre as classes sociais nos dez anos do lulismo},  volume={26},  ISSN={0103-6564},  url={https://doi.org/10.1590/0103-6564D20140012},  DOI={10.1590/0103-6564D20140012},  number={1},  journal={Psicologia USP},  publisher={Instituto de Psicologia da Universidade de São Paulo},  author={Singer, André},  year={2015},  month={Jan},  pages={7–14} }