@inbook{https://resolver.caltech.edu/CaltechAUTHORS:20161107-161002615,
    chapter = "Hierarchies and relations among data types",
    year = "1974",
    url = "https://resolver.caltech.edu/CaltechAUTHORS:20161107-161002615",
    id = "record",
    doi = "10.1145/1408800.1408867"
}