Official rule Book of the World Sport Stacking Association, Version 5.0 as released in 2009, "WSSA Sport Stacking Rule Book"(PDF). Archived from the original(PDF) on February 14, 2010. Retrieved January 28, 2010.
Official rule Book of the World Sport Stacking Association, Version 5.0 as released in 2009, "WSSA Sport Stacking Rule Book"(PDF). Archived from the original(PDF) on February 14, 2010. Retrieved January 28, 2010.