@article{PawelkeButzer1967,
  author    = {Pawelke, Siegfried and Butzer, Paul L.},
  title     = {Ableitungen von trigonometrischen Approximationsprozessen},
  series = {Acta scientiarum mathematicarum / Institutum Bolyaianum Universitatis Szegediensis},
  volume    = {28},
  journal   = {Acta scientiarum mathematicarum / Institutum Bolyaianum Universitatis Szegediensis},
  number    = {1-2},
  publisher = {n.a.},
  address   = {Szeged},
  isbn      = {0001-6969},
  pages     = {173 -- 183},
  year      = {1967},
  language  = {de}
}
@phdthesis{Mischke1963,
  author    = {Mischke, Winfried},
  title     = {Die Rechtsnatur des Nachlieferungsanspruchs beim Gattungskauf},
  publisher = {Universit{\"a}t zu K{\"o}ln},
  address   = {K{\"o}ln},
  pages     = {V, 46 Seiten},
  year      = {1963},
  language  = {de}
}
@book{OPUS4-10758,
  title     = {Baukeramik},
  organization    = {Ullersdorfer Werke},
  pages     = {40 Seiten},
  year      = {1925},
  language  = {de}
}