Dynamic formula cell referencing w/offset

Question

My formula:

=IFERROR(OFFSET('**2015**'!$A$1,MATCH($A8,'**2015**'!$A$2:$A$6000,0),0),0)

I need the parts in bold to be referencing a cell with a drop down (the drop down obviously has different dates which the formula needs to take into account) - which I guess makes it somewhat dynamic.

I have tried the indirect formula but failed to accomplish anything. I have ran out of ideas unfortunately.

Answer 1

Merely adding INDIRECT:

=IFERROR(OFFSET(INDIRECT(O2&"!$A$1"),MATCH($A8,INDIRECT(O2&"!$A$2:$A$6000"),0),0),0)  

Assumes dropdown value is in O2.