“…The result of this paper and others, [8,11,30], suggests that the z-measures with four parameters z, z ′ , a, b is the most general object that can be analyzed thoroughly, despite the fact that most quadruples (z, z ′ , a, b) do not have any representation theoretic origin. The recent paper [31] indicates that the BC type z-measures admit further a natural one-parameter θ > 0 degeneration (all papers cited before treat BC z-measures with θ = 1) and it would be interesting to study them.…”