@Work{OL2950945W,
    title: {Comet},
    author: {Carl Sagan and Ann Druyan},
    first_publish_year: {1985}
}

@Author{OL450295A,
    name: {Carl Sagan},
    birth_date: {9 November 1934}
    , death_date: {20 December 1996}
}
@Author{OL1433905A,
    name: {Ann Druyan},
    birth_date: {1949}
}