@book{heuser,
    author = "Heuser, Harro",
    title = "Gew{\"o}hnliche Differentialgleichungen",
    subtitle = "Einf{\"u}hrung in Lehre und Gebrauch",
    publisher = "Vieweg+Teubner Verlag",
    year = "2009",
    edition = "6",
    pages = "453,460,462",
}

@book{grune,
    author = "{Gr{\"u}ne, Lars} and {Junge, Oliver}",
    title = "Gew{\"o}hnliche Differentialgleichungen",
    subtitle = "Eine Einführung aus der Perspektive der dynamischen Systeme",
    publisher = "Vieweg+Teubner Verlag",
    year = "2009",
    pages = "10--16",
}