Complex Multi-Sheet Vlookup for Cross Workbook Reference

Using this formula to lookup my value across multiple worksheets and return the reference once found. Since I found this formula online, I'm not exactly sure how I can edit to incorporate the function across a different workbook. I've also heard that some sort of Index Match (besides the one in this formula) could be a better use, but I'm the type that defaults to vlookup so much, I wouldn't know how.

Quick explanation of this one: cycles through sheets until the reference and value are found then marks a "1" for the sheet with the value and "0" for the other sheets, allowing the function to be versatile in the array section of the vlookup.

=VLOOKUP(A4,INDIRECT("'"&INDEX(SheetList,MATCH(1,--(COUNTIF(INDIRECT("'"&SheetList&"'!$A$1:$c$4"),A4)>0),0))&"'!$A$1:$c$4"),2,FALSE)

I'm guessing the answer is to add the title of the workbook in where there is a

INDIRECT("'" ...

to this

INDIRECT("'[2017 Test Doc.xlsx] ..."

but I cannot get it to work.

Any guidance is much appreciated!