@book { ResearchMethodsProposalGoogle,
    title = "Research Methods Proposal - Google",
    author = "Sven {Elmers}",
    year = "2011",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783656042464",
    url = "https://www.hausarbeiten.de/document/181279"
}