@other{https://resolver.caltech.edu/CaltechCSTR:1984.5140-tr-84,
    title = "Hierarchy of Graph Isomorphism Testing",
    url = "https://resolver.caltech.edu/CaltechCSTR:1984.5140-tr-84",
    id = "record",
    doi = "10.7907/1hkhk-c5a29"
}