D. Glazebrook, K., On a family of prior distributions for a class of Bayesian search models, Advances in applied probability , 25(3), 1993, pp. 714-716
We propose a two-parameter family of conjugate prior distributions for the number of undiscovered objects in a class of Bayesian search models. The family contains the one-parameter Euler and Heine families as special cases. The two parameters may be interpreted respectively as an overall success rate and a rate of depletion of the source of objects. The new family gives enhanced flexibility in modelling.