@Article{nowak-1989a,
  author         = {Martin Nowak and Karl Sigmund},
  title          = {Game-Dynamical Aspects of the Prisoner's Dilemma},
  year           = {1989},
  volume         = {30},
  pages          = {191--213},
  read-status    = {short-list},
  journal        = {Applied Mathematics and Computation},
  url            = {http://www.ped.fas.harvard.edu/pdf_files_old/ApplMathComp89.pdf},
  key            = {nowak-1989a}
}