@other{https://authors.library.caltech.edu/records/pp04a-k3d74,
    author = "Luxemburg, W. A. J.",
    title = "Non-Standard Analysis: Lectures on A. Robinson's Theory of Infinitesimals and Infinitely Large Numbers",
    year = "2017",
    url = "https://resolver.caltech.edu/CaltechAUTHORS:20170327-135729832",
    id = "https://authors.library.caltech.edu/records/pp04a-k3d74"
}


@other{https://authors.library.caltech.edu/records/k4m2c-khm74,
    author = "Luxemburg, W. A. J.",
    title = "Notes on the Theory of Integration : Ma 108",
    year = "2017",
    url = "https://resolver.caltech.edu/CaltechAUTHORS:20170327-135159965",
    id = "https://authors.library.caltech.edu/records/k4m2c-khm74"
}