10.1184/R1/6491087.v1 Peter Spirtes Peter Spirtes Clark N. Glymour Clark N. Glymour Causal structure among measured variables preserved with unmeasured variables Carnegie Mellon University 1990 Artificial intelligence. Statistical hypothesis testing. 1990-01-01 00:00:00 Journal contribution https://kilthub.cmu.edu/articles/journal_contribution/Causal_structure_among_measured_variables_preserved_with_unmeasured_variables/6491087 Department of Philosophy technical report