title: Letter: faster gas-chromatographic procedure for theophylline.
mesh_terms: D002849:Chromatography, Gas / Q000379:methods; D006801:Humans; D010634:Phenobarbital / Q000032:analysis; D013805:Theobromine / Q000032:analysis; D013806:Theophylline / Q000032:analysis*; D014970:Xanthines / Q000032:analysis
chemical_list: D014970:Xanthines; D013806:Theophylline; D013805:Theobromine; D010634:Phenobarbital