Microsoft Windows for Pen Computing: Programmer's Reference - Microsoft Corporation, Terry A. Ward - Google Books

http://books.google.de/books?id=gi0iAQAAIAAJ&q=pen+computing&dq=pen+computing&hl=de&sa=X&ei=r8DmUuWoCcqrtAbVlIHQAw&ved=0CDwQ6AEw

The official documentation to the Microsoft Windows for pen computing extensions, the software that integrates complete support for pen input devices in the Windows environment. Essential for any developer curious about pen-based computing.