State Bar of Texas, 1984.
U.S. Tax Court, 1984.
U.S. Court of Claims, 1985.
U.S. Northern District of Texas, 1987.
U.S. District of Colorado, 1997.
U.S. Southern District of Texas, 1998.
U.S. Court of Appeals 5th Circuit, 1999.
U.S. Eastern District of Texas, 2004.
U.S. Eastern District of Pennsylvania, 2010.