@book{https://resolver.caltech.edu/CaltechAUTHORS:20200623-151845332,
    title = "Morphological Astronomy",
    year = "1957",
    url = "https://resolver.caltech.edu/CaltechAUTHORS:20200623-151845332",
    id = "record",
    isbn = "978-3-642-87546-5",
    doi = "10.1007/978-3-642-87544-1"
}