Sibuya, Masaaki; Yamato, Hajime - In: Statistics & Probability Letters 25 (1995) 2, pp. 177-183
The joint distribution of ordered (or unordered) frequencies of a sample from random proportions is the Donnelly-Tavaré-Griffiths formula (or the Ewens sampling formula) if and only if the size-biased permutation of the random proportions has the GEM distribution.