|You're confusing us (well, at least me!) by your use of the terms workbook and worksheet.|
A workbook is an Excel document that contains 1 or more worksheets.
Therefore, when you say:
I have another workbook (B)
and then say:
I want the address to be displayed in cell b4 in worksheet B.
you confuse us. (me!)
It might be best if you referred to your workbooks as A and B and then used Sheet1, Sheet2, Sheet3, etc. to refer to your sheets.