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@Book{            Mendelson,
  Author        = "Mendelson, Elliott",
  date-added    = "2020-04-10 11:07:26 +0200",
  date-modified = "2021-12-28 13:03:42 +0100",
  Edition       = "Fourth Edition",
  Keywords      = "mathematical logic",
  Publisher     = "Chapman\&Hall",
  Title         = "Introduction to Mathematical Logic",
  Year          = "1997",
  File          = "Introduction to Mathematical Logic - Mendelson (0) (0) - a - a.pdf",
  file-2        = "Introduction to Mathematical Logic - Mendelson (1) (0) - a - a.pdf"
}

@Book{ Mendelson, Author = "Mendelson, Elliott", date-added = "2020-04-10 11:07:26 +0200", date-modified = "2021-12-28 13:03:42 +0100", Edition = "Fourth Edition", Keywords = "mathematical logic", Publisher = "Chapman\&Hall", Title = "Introduction to Mathematical Logic", Year = "1997", File = "Introduction to Mathematical Logic - Mendelson (0) (0) - a - a.pdf", file-2 = "Introduction to Mathematical Logic - Mendelson (1) (0) - a - a.pdf" }