@article{P. Caulkins2018, author = "Jonathan P. Caulkins", title = "{Price and Purity Analysis for Illicit Drug: Data and Conceptual Issues}", year = "2018", month = "6", url = "https://kilthub.cmu.edu/articles/journal_contribution/Price_and_Purity_Analysis_for_Illicit_Drug_Data_and_Conceptual_Issues/6471830", doi = "10.1184/R1/6471830.v1" }