Ker A \subset Ker B
I am trying to find a reference for the following results :
Let A and B be two matrices :
Ker A \subset Ker B if and only if there exists M such that B= MA
I already have a proof for this statement, but it looks like a classical algebraic result, so I'm looking for a reference to add in my paper, like a book or a paper..
Thanks in advance for any suggestions..