@book { ProblemfallCybermobbingSpitzensportlerindenneuenMedien,
    title = "Problemfall Cybermobbing: Spitzensportler in den neuen Medien",
    author = "Christian {Hirschberger}",
    year = "2013",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783656410379",
    url = "https://www.hausarbeiten.de/document/212733"
}