1. Ghosh, J. K. and Singh, R. (1966). Unbiased estimation of location and scale param-eters. Ann. Math. Statist. 37 1671–1675.
2. Halmos, P. R. (1946). The theory of unbiased estimation. Ann. Math. Statist. 17 34–43.
3. Hille, E. and Phillips, R. S. (1957). Functional analysis and semi-groups. Amer.Math. Soc. ColLPubl. 31.
4. Lehmann, E. L. and Scheffé, Henry (1950). Completeness, similar regions and un-biased estimation. Sankhyā 10 305–340.
5. Renyi, A. (1953). Neue Kriterien zum Vergleich Zweier Stichproben. Magyar Tud. Akad. Mat. Fiz. Oszt. Közl.2 243–265.