The two orientations used to study knuckle-ball effects. Also

Aerodynamics of the newly approved football for the English Premier League 2020–21 season

IIT Kanpur discovers knuckleball 2.0: This one goes zigzag in the air

Aerodynamics of the newly approved football for the English Premier League 2020–21 season

Pitch Grips and Changing Fastball Spin Rate - Driveline Baseball

Sungchan Hong's research works University of Tsukuba, Tsukuba and other places

PDF) A comparison of Jabulani and Brazuca non-spin aerodynamics

Aerodynamics of knuckle ball: Flow-structure interaction problem on a pitched baseball without spin - ScienceDirect

Effect of panel shape of soccer ball on its flight characteristics

Knuckleball Research

What are the advantages and disadvantages of using the knuckleball as a primary pitch in baseball? - Quora

Verlander's Grips, as shown during the game last night : r/baseball

PDF) Physics of knuckleballs

PDF) A comparison of Jabulani and Brazuca non-spin aerodynamics

John GOFF, Professor of Physics, PhD, Physics