Hfill refers to when BEBC ran with Hydrogen

This dataset only has free protons so can tune the Delta++
Total x-sec with W < 1.4 GeV, dSigma/dQ2 with W < 1.4 GeV
Also angular distributions!
P.S. There's a beautiful W plot showing the clear Delta++ peak on p273


P. Allen et al., Nucl. Phys. B176 (1980) 269 284 North-Holland

Might have journal name change; safest is to search for the above on inspireHEP