Adsorptive Stripping Voltammetric Determination of Trace Uranium with a Bismuth‐Film Electrode Based on the U (VI)→ U (V) Reduction Step of the Uranium‐Cupferron Complex - Kefala, Georgia; Economou, Anastasios; Voulgaropoulos, Anastasios (Electroanalysis: An International Journal Devoted to Fundamental and Practical Aspects of ElectroanalysisElectroanalysis: An International Journal Devoted to Fundamental and Practical Aspects of Electroanalysis, 2006)