The derivative of $f:\mathbb{R}^N \to \mathbb{R}^M$ is of the form $f':\mathbb{R}^N \to \mathbb{R}^{M \times N}$. I'd like to know how the double derivative look like, i.e, how would $f''$ be ? It maps from $\mathbb{R}^N$ to which space?
PS : Please suggest some good references on this topic.