The Arithmetic of Elliptic Curves
《The Arithmetic of Elliptic Curves》 · 第 428 页 · Appendix C，Section 11「Complex Multiplication」，定义段
For any elliptic curve $E/K$, a Weber function on $E/K$ is a morphism defined over $K$ of the form $\phi_E:E\to E/\operatorname{Aut}(E)\cong\mathbb P^1$.