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@Book{            Niven,
  Author        = "Niven, Ivan",
  date-added    = "2020-04-10 11:07:26 +0200",
  date-modified = "2020-04-10 11:07:27 +0200",
  Publisher     = "Random House",
  Title         = "Mathematics of Choice - How to Count without Counting",
  Year          = "1965",
  File          = "Mathematics of Choice - How to Count without Counting - Niven (0) (0) - a - a.pdf"
}

@Book{ Niven, Author = "Niven, Ivan", date-added = "2020-04-10 11:07:26 +0200", date-modified = "2020-04-10 11:07:27 +0200", Publisher = "Random House", Title = "Mathematics of Choice - How to Count without Counting", Year = "1965", File = "Mathematics of Choice - How to Count without Counting - Niven (0) (0) - a - a.pdf" }