@other{https://thesis.library.caltech.edu/id/eprint/6895,
    author = "Bills, Bruce Gordon",
    title = "A harmonic and statistical analysis of the topography of the earth, moon and Mars",
    year = "1978",
    url = "https://resolver.caltech.edu/CaltechTHESIS:04092012-114720525",
    id = "https://thesis.library.caltech.edu/id/eprint/6895",
    doi = "10.7907/SM57-8B66"
}