@article{WaltonGordon2015,
  author    = {Douglas Walton and Thomas F. Gordon},
  title     = {Formalizing informal logic},
  journal   = {Informal logic : reasoning and argumentation in theory and practics},
  volume    = {35},
  number    = {4},
  pages     = {508 -- 538},
  year      = {2015},
}