These are the major periodical indexes to use for finding criticism in journals. See Electronic Indexes for Humanities Research for details. You can access them directly from this page if you are on campus. The following sources can help you with this. Not all of you will find a source for manuscripts for your author.
Some manuscripts are in private collections or retained by the author's themselves.
This tells you the year and page number of the volume you need. 1985 through 1987 must be searched independently. The series is current through 1987. As noted above, there may not be any formal collections of manuscripts for your author. These large olive green volumes, seven hundred and fifty-three of them, are located in the reference collection.