@book{SalenZ04,
  title = {Rules of play: game design fundamentals},
  author = {Katie Salen and Eric Zimmerman},
  year = {2004},
  url = {http://www.worldcat.org/oclc/56961648},
  researchr = {https://researchr.org/publication/SalenZ04},
  cites = {0},
  citedby = {0},
  publisher = {MIT Press},
  isbn = {9780262240451},
}