1. Balaram V and Gnaneswara Rao T 2003Atomic Spectrosc. 24 206
2. Balaram Vet al 2000Indian J. Chem. A39 567
3. Balaram V, Reddy MRP, Munirathnam N R and Anjaiah K V 2005Atomic Spectrosc. (communicated)
4. Baumann H and Pavel J 1989Microchim. Acta [Wien] III 413
5. Close K J and Yarwood J 1971An introduction to semiconductors (London: Heinemann)