Séminaire Lotharingien de Combinatoire, B15d (1986).
[Formerly: Publ. I.R.M.A. Strasbourg, 1987, 340/S-15, p.
It is shown that an identity recently obtained by Székely is
just equivalent to the Pfaff-Saalschütz identity. In the light
of this observation, it is then easy to find a q-analogue.
The paper has been finally published under the same title in
J. Combin. Theory, Ser. A 51 (1989), 141-143.