As noted in Aedia's answer, WCAG 2.0 accessibility guidelines recommend that the linked text should described the purpose of the link.
In your example, I would favour linking the full sentence:
John Q. claims that pigs can fly.
There are couple of other aspects to consider:
- Are "inline" links the best way of avoiding links like "More details
- Where would the user expect a link to go to?
Certainly inline links are popular in blogs, but as an alternative you can consider explicitly mentioning the source of the link, at the cost of slightly interrupting the flow of your piece:
John Q. claims that pigs can fly (see Flights of Fantasy, Porcine News, Issue 3.).
If you do decide to stick with inline links, users' expectations will be shaped by the consistency with which you link to various sources. Fair warning of potentially undesirable links should be given. For example, your readers may expect links to explicit content, or links to large PDFs, to be flagged, depending on where your content is appearing.
You can find a good example of inline linking in BBC sports journalist Phil McNulty's blog. His blog targets a mainstream public audience. He uses long link anchors that describe the content of link destinations, and typically links to other sports journalism articles on the BBC website or from national newspapers.