![Urine labeling with orally applied marker substances in drug substitution therapy]()
Urine labeling with orally applied marker substances in drug substitution therapyHuppertz, Bernd; Gauchel, Gisela; Feiertag, Heribert; Schweizer, Hermann; Krieger, Horst; Richter, Francois; Heinz, Helmut; Blanke, Joerg; Gastpar, Markus; Keller, Ruprecht · Clinical Chemistry and Laboratory Medicine · 2004