Web Dynpro for ABAP Tips and Tricks / Best Practices 2010

http://zbalai.com/_abap/content/420_web_dynpro_for_abap_tips_and_tricks/Web_Dynpro_for_ABAP_Tips_and_Tricks_V07.pdf

 

SAP PI/XI Interface Problems and Solutions

http://zbalai.com/_abap/content/400_online_interfaces_using_pixi/Online_Interfaces_using_PIXI_V04.pdf

 

Very Basic ABAP tutorial

http://zbalai.com/_abap/content/120_Tutorial/abap_tutorial.html