电子邮件收发系统的研究与设计,这是一个非常好的参考文档。值得向大家推荐，所以资源共享。-Email delivery system and its design, this is a very good reference document. To recommend, so sharing of resources.

用VC++编写的邮件客户端软件（参考设计）-Written with VC++ mail client software (reference design)