@book { ReprsentationkonvexerObjektedurchlineareConstraintsinGeoinformationssystemen,
    title = "Repräsentation konvexer Objekte durch lineare Constraints in Geoinformationssystemen",
    author = "Ulrich {Frenkel}",
    year = "1997",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    url = "https://m.diplom.de/document/216443"
}