@article{HardtMartinMeissburgeretal.1978,
  author    = {Hardt, Arno and Martin, S. and Meißburger, J. and Retz, R. and Wimmer, J.},
  title     = {The cryopump system of the QQDDQ magnet spectrometer BIG KARL},
  series = {Vacuum. Vol. 28, iss. 10-11},
  journal   = {Vacuum. Vol. 28, iss. 10-11},
  issn      = {1879-2715 (E-Journal); 0042-207X (Print)},
  pages     = {483},
  year      = {1978},
  language  = {en}
}
@article{Helsper1978,
  author    = {Helsper, Christoph},
  title     = {Particle Size Distributions of Combustion Aerosols / Fißan, H.J.; Franzen, H.; Helsper, C.},
  series = {Atmospheric pollution 1978 : proceedings of the 13. International Colloquium, UNESCO Building, Paris, France, April 25-28, 1978 / ed. by Michel M. Benarie.},
  journal   = {Atmospheric pollution 1978 : proceedings of the 13. International Colloquium, UNESCO Building, Paris, France, April 25-28, 1978 / ed. by Michel M. Benarie.},
  publisher = {Elsevier},
  address   = {Amsterdam [u.a.]},
  isbn      = {0-444-41691-9},
  pages     = {291 S.},
  year      = {1978},
  language  = {en}
}