The Google Books settlement (which is currently being investigated by the Department of Justice, among other people) clearly includes sheet music. How you may ask? Thank your friendly librarians…and see Music Publishing and the Google Books Settlement and Why Music Publishers and their Licensees Should Care About the Google Books Settlement
The National Music Publishers Association and the Harry Fox Agency sent an alert to their members informing them of what to do that is an excellent summary of the truly bizarre situation that Google has created for songwriters and publishers around the world and is well worth reading. Actually is required reading if you are responsible for adminstering any songs, including your own.
Remember–don’t think that this just affects Americans, it doesn’t. It affects everyone.