On period relations for automorphic 43f-functions I
F. Januszewski, Transactions of the American Mathematical Society 371 (2018) 6547–6580.

Integral representation and sharp asymptotic results for some Heckman-Opdam hypergeometric functions of type BC
M. Rösler, M. Voit, Transactions of the American Mathematical Society 368 (2016) 6005–6032.