Vlookup >> Different workbook with multiple sheet

Hi

How can I Vlookup to different workbook with multiple sheet?
I will need to summarize my order Order-A and Order-B. The sheet on Order-A and Order-B will keep on growing.

Please help~

Thanks

Please try at B4 of Summary of Order.xlsx
Drag to C4 and Drag Down, You need to keep all files open.
=INDIRECT("'[Order Received - "&LEFT($A4,1)&".xlsx]"&$A4&"'!$B"&COLUMN(B4)+2)

Thanks Bo_Ry

Is there any other else solution beside to keep both files open??