@other{https://thesis.library.caltech.edu/id/eprint/309,
    author = "Dwire, Oliver Scott",
    title = "A Study of Pressure Drop in Helical Coils",
    year = "1949",
    url = "https://resolver.caltech.edu/CaltechETD:etd-01232009-095750",
    id = "https://thesis.library.caltech.edu/id/eprint/309",
    doi = "10.7907/GV93-7D64"
}


@other{https://thesis.library.caltech.edu/id/eprint/512,
    author = "Weatherup, Robert Alexander",
    title = "An Experimental Investigation of the Pressure Loss in Flow Through Helical Coils",
    year = "1949",
    url = "https://resolver.caltech.edu/CaltechETD:etd-02052009-133758",
    id = "https://thesis.library.caltech.edu/id/eprint/512",
    doi = "10.7907/KZ8G-V819"
}