return _externSheetRecord.getREFRecordAt(externSheetNumber).getIndexToFirstSupBook();
}
public short addSheetIndexToExternSheet(short sheetNumber) {
ExternSheetSubRecord record = new ExternSheetSubRecord();
record.setIndexToFirstSupBook(sheetNumber);
record.setIndexToLastSupBook(sheetNumber);
_externSheetRecord.addREFRecord(record);
_externSheetRecord.setNumOfREFStructures((short)(_externSheetRecord.getNumOfREFStructures() + 1));
return (short)(_externSheetRecord.getNumOfREFStructures() - 1);
}