We establish a relation between the gamma matrices of the functional equations satisfied by zeta functions associated with prehomogeneous vector spaces and certain integrals related to the intertwining operator of degenerate principal series representations of general linear groups.
Fumihiro SATO. "Functional equations of prehomogeneous zeta functions and intertwining operators." J. Math. Soc. Japan 58 (4) 995 - 1008, October, 2006. https://doi.org/10.2969/jmsj/1179759534