High variation in purity of consumer-level illicit fentanyl samples in Los Angeles, September 2023-April 2025. - Shover CL; Koncsol AJ; Godvin ME; Goodman-Meza D; Pardo B; Poimboeuf M; Molina CA; Romero R; Feng J; Friedman JR (The International journal on drug policy, 2025)