  In a recent paper Richards and Zheng compute the determinant of a matrix
whose entries are given by beta-type integrals, thereby generalising an earlier
result by Dixon and Varchenko. They then use their result to obtain a
generalisation of the famous Selberg integral.
  In this note we point out that the Selberg-generalisation of Richards and
Zheng is a special case of an integral over Jack polynomials due to Kadell. We
then show how an integral formula for Jack polynomials of Okounkov and
Olshanski may be applied to prove Kadell's integral along the lines of Richards
and Zheng.
