• O'Keefe, Bryan (2015). "Bowling Release Ratio". usbcbowlingacademy.com. Archived from the original on April 2, 2016. (date is approximate) • "Adjusting Entry Angle". bowl.com (United States Bowling Congress, USBC). 2015. Archived from the original on April 17, 2017. (date is approximate)
"Technical Terms"(PDF). bowl.com. United States Bowling Congress. Archived(PDF) from the original on September 20, 2018. Retrieved 25 September 2018.
"Approved Ball List". bowl.com (United States Bowling Congress, USBC). Archived from the original on November 6, 2018.
Carrubba, Rich (June 2012). "Bowling Ball Evolution". BowlingBall.com (Bowlversity educational section). Archived from the original on September 17, 2018.
Martin, Jimmy (May 12, 2011). "The Evolution of Bowling Balls". BowlingBall.com (Bowlversity educational section). Archived from the original on September 26, 2022.
Carrubba, Rich (January 1, 2013). "Reactive Bowling Balls". BowlingBall.com (Bowlversity educational section). Archived from the original on August 6, 2020.
"Bowling Ball Reaction Keys". BowlingBall.com (Bowlversity educational section). July 28, 2016. Archived from the original on November 10, 2016.
Carrubba, Rich; Spear, Keith (September 9, 2016). "Ideal Bowling Ball Speed". Bowlingball.com (Bowlversity educational section). Archived from the original on February 5, 2025.
"Ball Dynamics and Hook Potential". BowlingBall.com (Bowlversity educational section). 2005. Archived from the original on November 24, 2005. Retrieved 25 September 2018.
Carrubba, Rich (February 4, 2013). "Bowling Ball Surface Grit Pads". BowlingBall.com (Bowlversity educational section). Archived from the original on November 11, 2020.
"Bowling"(PDF). Spalding's Athletic Library. Vol. 1, no. 3. New York: American Sports Publishing Company. December 1892. Archived from the original(PDF) on March 27, 2020.
• O'Keefe, Bryan (2015). "Bowling Release Ratio". usbcbowlingacademy.com. Archived from the original on April 2, 2016. (date is approximate) • "Adjusting Entry Angle". bowl.com (United States Bowling Congress, USBC). 2015. Archived from the original on April 17, 2017. (date is approximate)
web.archive.org
"Bowling"(PDF). Spalding's Athletic Library. Vol. 1, no. 3. New York: American Sports Publishing Company. December 1892. Archived from the original(PDF) on March 27, 2020.
Carrubba, Rich (June 2012). "Bowling Ball Evolution". BowlingBall.com (Bowlversity educational section). Archived from the original on September 17, 2018.
Martin, Jimmy (May 12, 2011). "The Evolution of Bowling Balls". BowlingBall.com (Bowlversity educational section). Archived from the original on September 26, 2022.
Carrubba, Rich (January 1, 2013). "Reactive Bowling Balls". BowlingBall.com (Bowlversity educational section). Archived from the original on August 6, 2020.
"Bowling Ball Reaction Keys". BowlingBall.com (Bowlversity educational section). July 28, 2016. Archived from the original on November 10, 2016.
• O'Keefe, Bryan (2015). "Bowling Release Ratio". usbcbowlingacademy.com. Archived from the original on April 2, 2016. (date is approximate) • "Adjusting Entry Angle". bowl.com (United States Bowling Congress, USBC). 2015. Archived from the original on April 17, 2017. (date is approximate)
Carrubba, Rich; Spear, Keith (September 9, 2016). "Ideal Bowling Ball Speed". Bowlingball.com (Bowlversity educational section). Archived from the original on February 5, 2025.
"Ball Dynamics and Hook Potential". BowlingBall.com (Bowlversity educational section). 2005. Archived from the original on November 24, 2005. Retrieved 25 September 2018.
"Technical Terms"(PDF). bowl.com. United States Bowling Congress. Archived(PDF) from the original on September 20, 2018. Retrieved 25 September 2018.
Carrubba, Rich (February 4, 2013). "Bowling Ball Surface Grit Pads". BowlingBall.com (Bowlversity educational section). Archived from the original on November 11, 2020.