Rao, C.R. (1982) Diversity and dissimilarity coefficients: a unified approach.
Theoretical Population Biology, 21, 24--43.Gini, C. (1912) Variabilita e mutabilita. Universite di Cagliari III, Parte II.
Simpson, E.H. (1949) Measurement of diversity. Nature, 163, 688.
Champely, S. and Chessel, D. (2002) Measuring biological diversity using Euclidean metrics.
Environmental and Ecological Statistics, 9, 167--177.