@book { ObservationsonTransaction,
    title = "Observations on Transaction",
    subtitle = "A Discussion of Watzlawick’s Second Axiom",
    author = "Gerhard {Gelbmann}",
    year = "2002",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1093954"
}