@book{Girg:600,
      author        = "R. Girg and U. Lichtinger and T. Müller",
      title         = "{The MultiGradeMultiLevel-Methodology and its global
                       significance: Ladders of learning, variations, scientific
                       horizons}",
      publisher     = "S. Roderer Verlag",
      year          = "2011",
}