@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}
}
@article{Helsper1986,
  author    = {Helsper, Christoph},
  title     = {Kondensationskernz{\"a}hler und ihre Anwendung in der Reinraumtechnik},
  series = {Swiss Chem. 8 (1986)},
  journal   = {Swiss Chem. 8 (1986)},
  isbn      = {0251-1703},
  pages     = {63 -- 66},
  year      = {1986},
  language  = {de}
}
@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{Helsper1993,
  author    = {Helsper, Christoph},
  title     = {Integrit{\"a}tspr{\"u}fung an LF-Anlagen mit Hilfe von Pr{\"u}faerosolen},
  series = {Pharma-Technologie-Journal. 14 (1993), H. 2},
  journal   = {Pharma-Technologie-Journal. 14 (1993), H. 2},
  isbn      = {0931-9700},
  pages     = {36 -- 42},
  year      = {1993},
  language  = {de}
}
@article{Helsper1995,
  author    = {Helsper, Christoph},
  title     = {Probleme der Staubprobenahme bei der Filterpr{\"u}fung},
  series = {Filtrieren und Separieren (1995)},
  journal   = {Filtrieren und Separieren (1995)},
  isbn      = {0933-5927},
  pages     = {5 -- 13},
  year      = {1995},
  language  = {de}
}
@article{Helsper2002,
  author    = {Helsper, Christoph},
  title     = {Partikelmesstechnik},
  series = {Reinraumtechnik , Hrsg.: Gail, Lothar},
  journal   = {Reinraumtechnik , Hrsg.: Gail, Lothar},
  publisher = {Springer},
  address   = {Berlin [u.a.]},
  isbn      = {3-540-66885-3},
  pages     = {57 -- 82},
  year      = {2002},
  language  = {de}
}
@article{Helsper2003,
  author    = {Helsper, Christoph},
  title     = {Messverfahren zur Charakterisierung der Abscheidung luftgetragener Partikel in Filtern},
  series = {Schutzmaßnahmen vor mikrobiellen Belastungen des Innenraumes / VII. L{\"u}becker Fachtagung f{\"u}r Umwelthygiene. [Hrsg.:] Reinhard Keller ...},
  journal   = {Schutzmaßnahmen vor mikrobiellen Belastungen des Innenraumes / VII. L{\"u}becker Fachtagung f{\"u}r Umwelthygiene. [Hrsg.:] Reinhard Keller ...},
  publisher = {Inst. f. Medizinische Mikrobiologie u. Hygiene d. Med. Univ.},
  address   = {L{\"u}beck},
  pages     = {35 -- 61},
  year      = {2003},
  language  = {de}
}
@article{Helsper1988,
  author    = {Helsper, Christoph},
  title     = {Kondensationskernz{\"a}hler in der Reinraummeßtechnik - Meßbereichsgrenzen nach unten verschoben},
  series = {Reinraumtechnik. 5 (1988)},
  journal   = {Reinraumtechnik. 5 (1988)},
  pages     = {36 -- 39},
  year      = {1988},
  language  = {de}
}
@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{HelsperBartzFissanetal.1985,
  author    = {Helsper, Christoph and Bartz, H. and Fißan, H. J. and Kousaka, Y. (u.a.)},
  title     = {Response Characteristics for Four Condensation Nucleus Counters to Particles in the 3 to 50 nm Diameter Range / Bartz, H. ; Fißan, H. J. ; Helsper, C.; Kousaka, Y. ; Okuyama, K. ; Keady, R. Fruin, S. ; McMurry, P. H.; Pui, D. Y. H. ; Stolzenburg, M. R.},
  series = {Journal of Aerosol Science. 16 (1985), H. 5},
  journal   = {Journal of Aerosol Science. 16 (1985), H. 5},
  isbn      = {0021-8502},
  pages     = {443 -- 456},
  year      = {1985},
  language  = {en}
}