The Arithmetic of Elliptic Curves
《The Arithmetic of Elliptic Curves》 · 第 412 页 · Appendix A，关于 Deuring normal form 的习题
Assume that $\operatorname{char}(K)\ne3$. Prove that every elliptic curve over $\overline K$ has an equation of the form $E_\alpha:y^2+\alpha xy+y=x^3$, where $\alpha^3\ne27$. This is called Deuring normal form.