@article{HagemannHennings1981,
  author    = {Hagemann, Hans-J{\"u}rgen and Hennings, D.},
  title     = {Reversible Weight change of acceptor-doped BaTiO3. Hagemann, H. J.; Hennings, D.},
  series = {Journal of the American Ceramic Society. 64 (1981)},
  journal   = {Journal of the American Ceramic Society. 64 (1981)},
  isbn      = {0002-7820},
  pages     = {590 -- 594},
  year      = {1981},
  language  = {en}
}
@article{Zastrow1981,
  author    = {Zastrow, Udo},
  title     = {Die Einflußfunktionen der Einzelkraft und der Stufenversetzung in der anisotropen Vollebene},
  series = {Archive of Applied Mechanics - Ingenieur Archiv. 51 (1981), H. 1-2},
  journal   = {Archive of Applied Mechanics - Ingenieur Archiv. 51 (1981), H. 1-2},
  isbn      = {1432-0681},
  pages     = {89 -- 99},
  year      = {1981},
  language  = {de}
}
@article{Alt1981,
  author    = {Alt, Helmut},
  title     = {Wirtschaftlichkeitsberechnung von Investitionen mit dem programmierbaren Taschenrechner},
  series = {3 R international : RRR ; Rohre, Rohrleitungsbau, Rohrleitungstransport},
  volume    = {Jg. 20},
  journal   = {3 R international : RRR ; Rohre, Rohrleitungsbau, Rohrleitungstransport},
  number    = {H. 10},
  issn      = {0340-3386},
  pages     = {561 -- 565},
  year      = {1981},
  language  = {de}
}