@article{https://resolver.caltech.edu/CaltechAUTHORS:20140801-113026550,
    title = "Mode superposition in multi-degree of freedom systems using earthquake response spectrum data",
    journal = "Bulletin of the Seismological Society of America",
    year = "1962",
    url = "https://resolver.caltech.edu/CaltechAUTHORS:20140801-113026550",
    id = "record",
    issn = "0037-1106",
    volume = "52"
}


@other{https://resolver.caltech.edu/CaltechEERL:1961.EERL.1961.004,
    title = "Mode superposition methods applied to linear mechanical systems under earthquake type excitations",
    year = "1961",
    url = "https://resolver.caltech.edu/CaltechEERL:1961.EERL.1961.004",
    id = "record"
}