1. ASA (2005)Official Rules of Softball Team Edition. 2005 Edition. Oklahoma City, OK: Amateur Softball Association of America.
2. ASTM F 1888-02 (2002)Test method for compression-displacement of baseballs and softballs. West Conshohocken, PA, USA.
3. ASTM F 2219-05 (2005)Standard test methods for measuring high-speed bat performance. West Conshohocken, PA, USA.
4. ASTM F 2398-04cl (2004)Standard test method for masuring moment of inertia and center of percussion of a baseball or softball bat. West Conshohocken, PA, USA.
5. Biesen, E. (2006)Prediction of plastic deformation in aluminum softball bats using finite element analysis. MS Thesis, Washington State University, USA.