@book { PhilosophyofManatRecreationandLeisure,
    title = "Philosophy of Man at Recreation and Leisure",
    author = "Christopher Berry {Gray}",
    year = "2007",
    publisher = "Peter Lang Verlag",
    address = "New York, United States of America",
    url = "https://www.peterlang.com/document/1102708"
}