private static String GetReferencePrintArea(String sheetName, int startC, int endC, int startR, int endR)
{
//windows excel example: Sheet1!$C$3:$E$4
CellReference colRef = new CellReference(sheetName, startR, startC, true, true);
CellReference colRef2 = new CellReference(sheetName, endR, endC, true, true);
return "$" + colRef.CellRefParts[2] + "$" + colRef.CellRefParts[1] + ":$" + colRef2.CellRefParts[2] + "$" + colRef2.CellRefParts[1];
}