Hi Darrell: The footnote references a will filed at Norfolk England: Court of the Bishop of Norwich (Episcopal) Will Registry. Each registry volume is named for the first testator in the book. Specifically, Doke covers wills dtd from 1436-1444. "Reg. Doke, Norw. fol. 53" is the 53rd entry in the volume entitled 'Doke' containing wills registered in the Court of the Bishop of Norwich.
It's an ancient reference system - kinda puzzling, really, until one has to use it. But, there it is. I think Family Search has a full listing of the registry names if you ever run across it again, there are almost a hundred volumes, all named.
Cheers.