• DOI http://dx.doi.org/10.18177/sym.2011.51.sr.19
  • PDF https://www.jstor.org/stable/26513060

  • DOI http://dx.doi.org/10.18177/sym.2011.51.fr.8944
  • PDF https://www.jstor.org/stable/26513074

  • DOI http://dx.doi.org/10.18177/sym.2011.51.itm.9493
  • PDF https://www.jstor.org/stable/26513072