@book { FormulaFlexibility,
    title = "«Formula Flexibility»",
    author = "B. {Steinbach-van der Veen}",
    year = "2018",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/b13785",
    url = "https://www.peterlang.com/document/1068361"
}