@article{Goldfeld1974ASP,
title={A Simple Proof of Siegel's Theorem.},
author={D M Goldfeld},
journal={Proceedings of the National Academy of Sciences of the United States of America},
year={1974},
volume={71 4},
pages={1055}
}

A brief and simple proof of Siegel's celebrated theorem that h(d) >> d(1/2-[unk]), as d --> infinity, is given. Here h(d) denotes the class number of the quadratic field Q([unk]-d). Simple proofs that do not make use of algebraic number theory have been previously given by Estermann and Chowla.