[MSDN Library June 1998] ISNULL( ) Function (29.335027100271%)
MSDN Library Visual Studio 6.0 > Visual FoxPro Documentation > Reference > A to Z Language Reference
[MSDN Library June 1998] IsNull Function (21.9608472400513%)
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 (21.3029525032092%)
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 (21.1030468221771%)
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 (17.5629058441558%)
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