Let $X\hookrightarrow\mathbb{P}^n_{\mathbb{F}_q}$ be a pure dimensional projective scheme of dimension $d$. So we know a trivial estimate of the number of $X(\mathbb F_q)$ is that $\#X(\mathbb F_q)\leqslant\deg(X)(q^d+\cdots+1)$.
I want to know where I can find a reference of the proof of this result. Only requirement is that it must be a "published" reference.
Thank you.