}
public String toFormulaString(Workbook book)
{
SheetReferences refs = book == null ? null : book.getSheetReferences();
StringBuffer retval = new StringBuffer();
if ( refs != null )
{
retval.append( refs.getSheetName( this.field_1_index_extern_sheet ) );
retval.append( '!' );
}
retval.append( ( new CellReference( getFirstRow(), getFirstColumn(), !isFirstRowRelative(), !isFirstColRelative() ) ).toString() );
retval.append( ':' );
retval.append( ( new CellReference( getLastRow(), getLastColumn(), !isLastRowRelative(), !isLastColRelative() ) ).toString() );