• DOI https://doi.org/10.18177/sym.2017.57.rev.11362
  • PDF https://www.jstor.org/stable/26574468

  • DOI http://dx.doi.org/10.18177/sym.2016.56.fr.11107
  • PDF https://www.jstor.org/stable/26574451

  • PDF https://www.jstor.org/stable/40374259