The best place to start a literature search on post-polio exercises is to tap the Post-Polio Health International's resources. They have a variety of the latest articles from the best researchers in the world on this very specialized topic. They can be reached by calling 314-534-0475 or connecting with their website at Post-polio Health International.
You may also want to do a literature search of the medical journals at your local library. Librarians can help you do a "Medline search" for pertinent medical publications or you can do one on your own by tapping into the internet, going to Medscape.