Be sure to put your play's name in quotes if it is more than one word.
"Measure for Measure"
"All's Well That Ends Well"
etc.
Includes books, articles, and more published on modern languages, literatures, folklore, and linguistics.
Limit your search to Shakespeare Criticism under the Publication Title section on the left side of your search results page.
The index is your friend.
"All's Well that Ends Well"
Covers all aspects of theatre and performance in 126 countries.