@article{Helsper1986,
  author    = {Helsper, Christoph},
  title     = {Measurement Techniques For Ultrafine Particles},
  series = {Ultrafine aerosols. Properties and behaviour. Proceedings of the 1. International Workshop on Ultrafine Aerosols of the Sonderforschungsbereich 209 'Stoff- und Energietransport in Aerosolen' -'Mass and energy transfer in aerosols'-, held at the Univ. of Duisburg on Sept. 29, 1986},
  journal   = {Ultrafine aerosols. Properties and behaviour. Proceedings of the 1. International Workshop on Ultrafine Aerosols of the Sonderforschungsbereich 209 'Stoff- und Energietransport in Aerosolen' -'Mass and energy transfer in aerosols'-, held at the Univ. of Duisburg on Sept. 29, 1986},
  address   = {Duisburg},
  year      = {1986},
  language  = {en}
}
@article{HelsperBartz1987,
  author    = {Helsper, Christoph and Bartz, H.},
  title     = {Theoretische Bestimmung des Abscheidegrades eines Filters bei verschiedenen Betriebszust{\"a}nden / Bartz, H. ; Helsper, C.},
  series = {Staub, Reinhaltung der Luft. 47 (1987)},
  journal   = {Staub, Reinhaltung der Luft. 47 (1987)},
  isbn      = {0039-0771},
  pages     = {112 -- 114},
  year      = {1987},
  language  = {de}
}
@article{HelsperMoelterMoelter1986,
  author    = {Helsper, Christoph and M{\"o}lter, W. and M{\"o}lter, L.},
  title     = {Korngr{\"o}ßenanalyseverfahren f{\"u}r trockene Pulver und St{\"a}ube von 0,5-25 µm},
  series = {Chemie-Technik. 16 (1986)},
  journal   = {Chemie-Technik. 16 (1986)},
  isbn      = {0340-9961},
  pages     = {140 -- 144},
  year      = {1986},
  language  = {de}
}
@article{HelsperMoelterWillemer1987,
  author    = {Helsper, Christoph and M{\"o}lter, W. and Willemer, W.},
  title     = {Fast and Automated Testing of Filter Media / M{\"o}lter, W. ; Helsper, C. ; Willemer, W.},
  series = {FILTECH Conference 1987 : Utrecht, Holland; September 23 - 25 1987 / org. by the Filtration Society , Vol. 1.},
  journal   = {FILTECH Conference 1987 : Utrecht, Holland; September 23 - 25 1987 / org. by the Filtration Society , Vol. 1.},
  publisher = {Filtration Society},
  address   = {Loughborough},
  pages     = {106 -- 112},
  year      = {1987},
  language  = {en}
}
@article{Helsper1979,
  author    = {Helsper, Christoph},
  title     = {Evaluation of Particle Size Distributions by Means of Particle Counters / Fißan, H. J. ; Helsper, C.},
  series = {Proceedings of the First Workshop of Particulate Control : 16. - 17. March 1978, Kernforschung-sanlage J{\"u}lich GmbH / prepared by U.S. Environmental Protection Agency, Off. of Research and Development, Washington, D.C, 1979,},
  journal   = {Proceedings of the First Workshop of Particulate Control : 16. - 17. March 1978, Kernforschung-sanlage J{\"u}lich GmbH / prepared by U.S. Environmental Protection Agency, Off. of Research and Development, Washington, D.C, 1979,},
  publisher = {Zentralbibliothek d. Kernforschungsanlage J{\"u}lich [in Komm.]},
  address   = {J{\"u}lich},
  pages     = {495 S.: Ill., graph. Darst.},
  year      = {1979},
  language  = {en}
}
@book{HelsperBesslingKiocketal.1979,
  author    = {Helsper, Christoph and Beßling, Harro and Kiock, R. and Fißan, H. J.},
  title     = {Experimentelle Untersuchung der Partikelanzahlkonzentration im Windkanal f{\"u}r den Einsatz von laseranemometrischen Verfahren / Beßling, Harro; Kiock, R.; Helsper, C.; Fißan, H. J.},
  publisher = {DFVLR},
  address   = {K{\"o}ln},
  pages     = {48 S.},
  year      = {1979},
  language  = {de}
}
@article{HelsperFissan1979,
  author    = {Helsper, Christoph and Fißan, H. J.},
  title     = {Numerical Simulation Studies and Data Reduction for Size Classifying Measurement Techniques / Fißan, H. J.; Helsper, C.},
  series = {Aerosols in science, medicine and technology : conference / Gesellschaft f{\"u}r Aerosolforschung 7. 1979.},
  journal   = {Aerosols in science, medicine and technology : conference / Gesellschaft f{\"u}r Aerosolforschung 7. 1979.},
  pages     = {199 -- 205},
  year      = {1979},
  language  = {en}
}
@article{HelsperFissan1980,
  author    = {Helsper, Christoph and Fißan, H. J.},
  title     = {Numerical Simulation Studies and Data Reduction for Size Classifying Measurement Techniques / Fißan, H. J.; Helsper, C.},
  series = {Advances in Particle Sampling and Measurement: Proceedings, Daytona Beach, EPA 600/9 80 004, 1980},
  journal   = {Advances in Particle Sampling and Measurement: Proceedings, Daytona Beach, EPA 600/9 80 004, 1980},
  publisher = {National Technical Information Service},
  address   = {Springfield, Va.},
  pages     = {VII, 409 S.},
  year      = {1980},
  language  = {en}
}
@article{HelsperFissanMugglietal.1980,
  author    = {Helsper, Christoph and Fißan, H. J. and Muggli, J. and Scheidweiler, A.},
  title     = {Particle Number Distributions of Aerosols from Test Fires},
  series = {Journal of Aerosol Science. 11 (1980), H. 5-6},
  journal   = {Journal of Aerosol Science. 11 (1980), H. 5-6},
  isbn      = {0021-8502},
  pages     = {439 -- 446},
  year      = {1980},
  language  = {en}
}
@article{HelsperFissan1981,
  author    = {Helsper, Christoph and Fißan, H. J.},
  title     = {Response Characteristic of a Polytec HC-15 Optical Particle Counter},
  series = {Aerosols in science, medicine and technology : Physical and chemical properties of aerosols : Association for Aerosol Research: annual conference. 1980 : Gesellschaft f{\"u}r Aerosolforschung: annual conference. 1980 : Aerosols in science, medicine and technology : Physical and chemical properties of aerosols : Associa-tion for Aerosol Research: annual conference. 1980 : Gesellschaft f{\"u}r Aerosolforschung: annual conference. 1980 : Schmallenberg, 22.10.80 - 24.10.80},
  journal   = {Aerosols in science, medicine and technology : Physical and chemical properties of aerosols : Association for Aerosol Research: annual conference. 1980 : Gesellschaft f{\"u}r Aerosolforschung: annual conference. 1980 : Aerosols in science, medicine and technology : Physical and chemical properties of aerosols : Associa-tion for Aerosol Research: annual conference. 1980 : Gesellschaft f{\"u}r Aerosolforschung: annual conference. 1980 : Schmallenberg, 22.10.80 - 24.10.80},
  publisher = {Pergamon Pr.},
  address   = {Oxford},
  pages     = {287 -- 292},
  year      = {1981},
  language  = {en}
}