The phrasing suggests you might be looking for a review of a specific PDF file or a site offering it. The Blockade by Aaron Nimzowitsch (Chess Perspective)
Nimzowitsch argues that a passed pawn or a strong pawn center should be neutralized by placing a piece (ideally a Knight) directly in front of it. Download Blockade nimz pdf
If you are looking for a review of Nimzowitsch’s work on the blockade: The phrasing suggests you might be looking for