@Article{         10.2307/2371809,
  Author        = "Post, Emil L.",
  date-added    = "2021-03-08 14:31:34 +0100",
  date-modified = "2021-03-08 14:31:34 +0100",
  ISSN          = "00029327, 10806377",
  Journal       = "American Journal of Mathematics",
  Number        = "2",
  Pages         = "197--215",
  Publisher     = "Johns Hopkins University Press",
  Title         = "Formal Reductions of the General Combinatorial Decision Problem",
  URL           = "http://www.jstor.org/stable/2371809",
  Volume        = "65",
  Year          = "1943",
  bdsk-url-1    = "http://www.jstor.org/stable/2371809",
  File          = "Formal Reductions of the General Combinatorial Decision Problem. - 2371809 - p.pdf"
}

@Article{ 10.2307/2371809, Author = "Post, Emil L.", date-added = "2021-03-08 14:31:34 +0100", date-modified = "2021-03-08 14:31:34 +0100", ISSN = "00029327, 10806377", Journal = "American Journal of Mathematics", Number = "2", Pages = "197--215", Publisher = "Johns Hopkins University Press", Title = "Formal Reductions of the General Combinatorial Decision Problem", URL = "http://www.jstor.org/stable/2371809", Volume = "65", Year = "1943", bdsk-url-1 = "http://www.jstor.org/stable/2371809", File = "Formal Reductions of the General Combinatorial Decision Problem. - 2371809 - p.pdf" }