@book{PSTricks,
  author = "H[erbert] Vo{\ss}",
  publisher = "Lehmanns Media",
  title = "PSTricks -- {Grafik} mit {PostScript} f{\"u}r {\TeX} und {\LaTeX}",
  series = "DANTE Arbeitshefte",
  edition = "5.",
  year = 2008,
}
@book{beamer,
  author = "Herbert Vo{\ss}",
  publisher = "Lehmanns Media",
  title = "Pr{\"a}sentationen mit {\LaTeX}",
  series = "DANTE Arbeitshefte",
  edition = "1.",
  year = 2009,
}