@article{T. Kelly2018, author = "Kevin T. Kelly", title = "{Version Spaces, Structural Descriptions and NP-Completeness}", year = "2018", month = "6", url = "https://kilthub.cmu.edu/articles/journal_contribution/Version_Spaces_Structural_Descriptions_and_NP-Completeness/6493097", doi = "10.1184/R1/6493097.v1" }