I don't think that OUP claims ownership of the words, but the information
in their formatting, eg. V.iii.7, p. ? -- which helps people locate
information.  Since the material is already on the Liberty Fund web site, I
think that Tony might be able to cite it that way.

In any case, intellectual property is an abomination in its present form. 
Libertarians used to oppose it as monopoly.  What happened to contemporary
Libertarians?

Michael Perelman