This code is from Charles Pettzold's "Programming Windows Sixth Edition" book:

```
public object Convert(object value, Type targetType, object parameter, string language) 
{ 
    return ((double)value).ToString("N0"); 
}

```

`ToString("N0")` is supposed to print the value with comma separators and no decimal points. I cannot find the reference to appropriate `ToString` overload and `"N0"` format in the documentation. Please point me to the right place in .NET documentation.