@book { NonprofitMarketingimSchulbereich,
    title = "Nonprofit-Marketing im Schulbereich",
    author = "Patrick {Ressler}",
    year = "2010",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-00286-7",
    url = "https://www.peterlang.com/document/1054307"
}