Conference ProceedingsPrevalence of Norhydrocodone in Authentic Hydrocodone Urine SpecimensPresenting section:Toxicology2011Gwak, Seongshin, Wonju SOUTH KOREA; Collins, Ayodele A., Midland TX; Park, Cade, Midland TX; Chester, Scot, Midland TX; Bourland, James A., Austin TXView the paperToxicology