@book { BeyondtheThreshold,
    title = "Beyond the Threshold",
    author = "Hein {Viljoen} and Chris N. {Van der Merwe}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "New York, United States of America",
    url = "https://www.peterlang.com/document/1102670"
}