UnicodeString unicode = sstRecord.getString(sst.getSSTIndex());
addTextCell(record, unicode.getString());
break;
case NumberRecord.sid: // Contains a numeric cell value
NumberRecord number = (NumberRecord) record;
addCell(record, new NumberCell(number.getValue()));
break;
case RKRecord.sid: // Excel internal number record
RKRecord rk = (RKRecord) record;
addCell(record, new NumberCell(rk.getRKNumber()));