title: [Studies on urinary calcium ion activity in urolithiasis. 1. Determination of calcium ion activity with an ion-selective electrode].
mesh_terms: D002118:Calcium / Q000652:urine*; D002138:Calibration; D004566:Electrodes; D006801:Humans; D014545:Urinary Calculi / Q000652:urine*
chemical_list: D002118:Calcium