X-31 Project Summary - The X-31 program logged an X-Plane record total of 524 flights in 52 months with 14 pilots. The program demonstrated the value of using thrust vectoring coupled with advanced flight control systems, to provide controlled flight to very high angles of atta - http://www.dfrc.nasa.gov/Newsroom/FactSheets/FS-009-DFRC.html
Navy News Service - Article titled "X-31 Flying Again at Pax River." - http://www.news.navy.mil/search/display.asp?story_id=1730
Rockwell/Messerschmitt-B-B X-31 - The X-31 was designed to break the "stall barrier", allowing it to flight at angles of attack which would typically cause an aircraft to stall resulting loss of control. - http://users.dbscorp.net/jmustain/x31.htm