Let $A=\mathbb{Q} [x_1,\dots,x_n]$ be the ring of polynomials with rational coefficients. Let $T$ be an $m\times n$ matrix with entries from $A$. Consider it as a morphism of $A$-modules $T\colon A^n\to A^m$.
The kernel of $T$ is a submodule of $A^n$. I heard that there is a notion of Grobner basis of such a submodule.
I will be happy to have a reference where this notion is defined and how to compute it in the above situation.
Remark. The notion of Grobner basis I googled deals with the special case of ideals in $A$.