@book { ImmigrationtotheUnitedStates,
    title = "Immigration to the United States",
    author = "Tom {Meckmann}",
    year = "2001",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783638980852",
    url = "https://www.hausarbeiten.de/document/99646"
}