@Book{OL7637879M,
    title: {The Wit and Wisdom of Mark Twain},
    author: {Mark Twain},
    publisher: {Dover Publications},
    year: {1998},
}

@Author{OL18319A,
    name: {Mark Twain},
    birth_date: {30 November 1835}
    , death_date: {21 April 1910}
}