[MSDN Library April 2000] #ifndef (68.4116809116809%)
MSDN Library - April 2000 > Platform SDK > User Interface Services > Windows User Interface > Resources > Resource Compiler > About Resource Files > Preprocessor Directives
[MSDN Library September 1992] #ifndef (48.9417989417989%)
Product Documentation > Windows 3.1 SDK > Programmer's Reference Volume 4: Resources > PART 2 Tools Reference > Chapter 13 Resource-Definition Statements
[MSDN Library September 1992] #ifndef Statement (34.4576819269022%)
Product Documentation > QuickC for Windows > Toolkit > PART 3 The Resource Compiler and Utilities > Chapter 8 Resource Script Statements > Dialog Control Statements