@other{https://resolver.caltech.edu/CaltechTHESIS:07282014-093054555,
    title = "Isotopic fractionation in sputtering",
    year = "1990",
    url = "https://resolver.caltech.edu/CaltechTHESIS:07282014-093054555",
    id = "record",
    doi = "10.7907/XEGH-4365"
}