1. Ayres G H and Baird S S 1961Talanta
7 237
2. Kolthoff I M and Belcher R 1957Volumetric Analysis (New York: Interscience Publishers, Inc.) vol. 3, p. 340 & 403
3. Pandu Ranga Rao V, Venugopala Rao K and Bhaskara Sarma P V R 1969Talanta
16 277
4. Sandell E B 1950Colorimetric Determination of Traces of Metals (New York: Interscience Publishers, Inc.) p. 50
5. Vogel A I 1961A Text Book of Quantitative Inorganic Analysis (London: Longmans Green) p. 309, 629