[MSDN Library June 1998] ISNULL( ) Function (100%)

MSDN Library Visual Studio 6.0 > Visual FoxPro Documentation > Reference > A to Z Language Reference

[MSDN Library June 1998] IsNull Function (35.9766081871345%)

MSDN Library Visual Studio 6.0 > Microsoft Office Development > Office 95 Documentation > Excel > Microsoft Excel/Visual Basic Reference > A-Z Reference

[MSDN Library June 1998] IsNull Function (35.0506822612086%)

MSDN Library Visual Studio 6.0 > Microsoft Office Development > Office 95 Documentation > Access > Microsoft Access 95 Language Reference > Part 2 A-Z Reference

[MSDN Library June 1998] IsNull Function (32.4402749605589%)

MSDN Library Visual Studio 6.0 > Microsoft Office Development > Office 97 Documentation > Office > Microsoft Office 97/Visual Basic Language Reference > Volume 5 > Microsoft Visual Basic for Applications Language Reference

[MSDN Library June 1998] IsNull (23.780303030303%)

MSDN Library Visual Studio 6.0 > Tools and Technologies > Windows CE Toolkit for Visual Basic 5.0 > Windows CE Toolkit for Visual Basic 5.0 > Windows CE Toolkit for Visual Basic 5.0 Help > Language Reference > Functions