@book { MixedMethodResearchQualitativeComparativeAnalysis,
    title = "Mixed Method Research - Qualitative Comparative Analysis",
    author = "Roland {Spitzlinger}",
    year = "2010",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783640631179",
    url = "https://www.hausarbeiten.de/document/151237"
}