• DOI http://dx.doi.org/10.18177/sym.2016.56.rev.11149
  • PDF https://www.jstor.org/stable/26574437

  • DOI http://dx.doi.org/10.18177/sym.2011.51.sr.14
  • PDF https://www.jstor.org/stable/26513065

  • PDF https://www.jstor.org/stable/40374506