I have a product of the form $e^{-tx}\times G_{p,q}^{m,n}\left(x\left|\begin{smallmatrix}\mathbf{a}_n, \mathbf{a}_{p-n}\\ \mathbf{b}_m, \mathbf{b}_{q-m}\end{smallmatrix}\right.\right)$. I need to write the product as Meijer's-G function. I know the shifting property $z^{\mu}G_{p,q}^{m,n}\left(x\left|\begin{smallmatrix}\mathbf{a}_n, \mathbf{a}_{p-n}\\ \mathbf{b}_m, \mathbf{b}_{q-m}\end{smallmatrix}\right.\right) = G_{p,q}^{m,n}\left(x\left|\begin{smallmatrix}\mathbf{a}_n+\mu, \mathbf{a}_{p-n}+\mu\\ \mathbf{b}_m+\mu, \mathbf{b}_{q-m}+\mu\end{smallmatrix}\right.\right)$ form NIST. Is there a similar property for this?
Also where can I find an academic reference (book/paper) about this subject (product of two Meijer G functions) or at least its special cases if any exists? I know this formulae exists Wolfram-MeijerG-product but I don't know how to use it for this case unfortunately!
Any help and hint is appreciated!
Thank you in advance!