@book { MobbingunterSchlern,
    title = "Mobbing unter Schülern",
    author = "Julia {Hanke}",
    year = "2008",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783640224951",
    url = "https://www.hausarbeiten.de/document/119516"
}