public boolean validCellRef(String cellRef) {
		boolean valid = false;
		String numbers = "0123456789";
		String letters = "ABCDEFGH";
		
		if(cellRef.length() == 2)
		{
			if(letters.indexOf(cellRef.substring(0, 1)) >= 0)
			{
				if(numbers.indexOf(cellRef.substring(1, 2)) >= 0)
				{
					valid = true;
				}
			}
		}
		else if(cellRef.length() == 3 && cellRef.substring(1).equals("10")) 
		{
			if(letters.indexOf(cellRef.substring(0, 1)) >= 0)
			{
				valid = true;
			}
		}
		return valid;
	}