@Work{OL3270906W,
    title: {Signals and Systems},
    author: {Alan V. Oppenheim and Alan S. Willsky},
    first_publish_year: {1983}
}

@Author{OL533640A,
    name: {Alan V. Oppenheim},
    birth_date: {1937}
}
@Author{OL1862585A,
    name: {Alan S. Willsky},
}