copying empty cells as empty

hi,
in my workbook i copy values from other sheets like so: ='otherSheet'!A5.
if the original cell is empty, the copied value is 0.
is there a way to make the empty cell to be copied as an empty cell?
thanks

thanks carim, but that doesn't solve my problem- when i use average function on those cells the 0 values are still taken into consideration.

so my problem actually is how to get an empty cell to be linked as empty on another workbook.
thanks