http://www.cis.ohio-state.edu/hypertext/faq/usenet/Copyright-FAQ/top.html
The Copyright Basics therein give an ample discussion of `fair use'
and left me believing that quoting Hart's work without permission
might be marginal ethically, although I doubt that the contemplated
quoting of it in a discussion forum would be actionable legally.
"Use the Web, Luke..."
- Larry