I read an article about the Rellich-Kondrachov embedding theorem in Sobolev spaces. Nevertheless, when I checked the refererence in Evans' PDE book, I only find the proof of the special case $W^{1,p}(\Omega)\subset\subset L^q(\Omega)$ where $\Omega\subset \mathbb{R}^n$ with $\partial \Omega \in C^1$, $1\le p<n$, and $1\le q<\frac{np}{n-p}$.
Do you know the proof (or references) for general result $W^{k,p}(\Omega)\subset\subset W^{l,q}(\Omega)$ whenever $k-\frac{n}{p} > l-\frac{n}{q}$?
You can find the general statement and proof in Chapter 6 of the book "Sobolev Spaces" by Robert A. Adams and John. J. F. Fournier.