Well, I'm not sure if John Donovan would agree.
I believe he was a research assistant for Michael Selig in the 1980's -
"Also available here online and in printed format by SoarTech Aero Publications is the book Airfoils at Low Speeds (aka SoarTech 8), which includes wind tunnel data on 54 airfoils tested at Reynolds numbers ranging from 60,000 to 300,000. The book contains extensive commentary and analysis. Testing was performed at Princeton University during 1987 and 1988 by Michael Selig, John Donovan and David Fraser. This work was the important precursor to the low Reynolds number airfoil research at UIUC."
Whether the S3021 & the SD3021 are one & the same airfoil with 2 designations, I am not sure at this stage. More digging to do.