@article{ZastrowRieder1980,
  author    = {Zastrow, Udo and Rieder, G.},
  title     = {Zur Eingrenzung der Eigenfrequenzen eines station{\"a}r schwingenden elastischen K{\"o}rpers mittels Integralgleichungen},
  series = {ZAMM - Zeitschrift f{\"u}r angewandte Mathematik und Mechanik. 60 (1980), H. 6},
  journal   = {ZAMM - Zeitschrift f{\"u}r angewandte Mathematik und Mechanik. 60 (1980), H. 6},
  isbn      = {1521-4001},
  pages     = {T149 -- T150},
  year      = {1980},
  language  = {de}
}
@book{Alt1980,
  author    = {Alt, Helmut},
  title     = {Allgemeine Elektrotechnik, Nachrichtentechnik, Impulstechnik f{\"u}r UPN-Rechner. (Anwendung programmierbarer Taschenrechner ; 2)},
  publisher = {Vieweg},
  address   = {Braunschweig [u.a.]},
  isbn      = {3-528-04151-X},
  pages     = {VII, 109 S. : graph. Darst.},
  year      = {1980},
  language  = {de}
}
@book{Alt1980,
  author    = {Alt, Helmut},
  title     = {Elektrische Energietechnik, Steuerungstechnik, Elektrizit{\"a}tswirtschaft f{\"u}r UPN-Rechner. (Anwendung programmierbarer Taschenrechner ; 6)},
  publisher = {Vieweg},
  address   = {Braunschweig [u.a.]},
  isbn      = {3-528-04180-3},
  pages     = {VIII, 118 S. : graph. Darst.},
  year      = {1980},
  language  = {de}
}
@article{Alt1980,
  author    = {Alt, Helmut},
  title     = {Kurzschlußstromberechnung},
  series = {Elektrizit{\"a}tswirtschaft},
  volume    = {Jg. 79},
  journal   = {Elektrizit{\"a}tswirtschaft},
  number    = {H. 10},
  issn      = {0013-5496},
  pages     = {379 -- 382},
  year      = {1980},
  language  = {de}
}