@other{https://resolver.caltech.edu/CaltechTHESIS:03092011-115217519,
    title = "The Absorption Coefficient of Hard Gamma-Rays",
    year = "1930",
    url = "https://resolver.caltech.edu/CaltechTHESIS:03092011-115217519",
    id = "record",
    doi = "10.7907/ZG7Q-QN03"
}