Ra. Gustafson, SOME Q-BETA AND MELLIN-BARNES INTEGRALS ON COMPACT LIE-GROUPS AND LIE-ALGEBRAS, Transactions of the American Mathematical Society, 341(1), 1994, pp. 69-119
Multidimensional generalizations of beta type integrals of Barnes, Ram
anujan, Askey-Wilson, and others are evaluated, These integrals are an
alogues of the summation theorems for multilateral hypergeometric seri
es associated to the simple Lie algebras of classical type and type G(
2). Many of these integrals can also be written as group integrals ove
r a compact Lie group or conjugation invariant integrals over the corr
esponding Lie algebra.