“Some Sources of Error in Laboratory Knock Ratings” by W. E. Adams and J. D. McCullough
In the late 1950s, researchers at Ethyl Corporation conducted a study to look at the effects on the Research Octane Number by various variables within the engine environment. This study highlighted the differences that can be seen when pieces of equipment on different engines are dissimilar. These differences were most notable when comparing different detonation pickups and errors when taking barometric pressure into account.
The study and its report are detailed below.