SAP ABAP开发指南 全面介绍 ABAP 不可多得开发指导-This documentation describes how to write application programs within the three-tier client/server architecture of the R/3 System.

dicop开发指南，快速开发三层系统，delphi下的最好三层工具。(Dicop development guide, the rapid development of three layers of system.)