Well, you need also something to create a link target.
Many times I create double linked hyperlinks for reference purposes as not all E-readers have automagical return support (like for instance the PRS-Tx):
- click the ref-link and you jump to a reference,
Code:
<a id="footnote1"></a><sup><a href="footnotes.xhtml#bookmark1">1</a></sup>
- click the reference and you jump back where you started.
Code:
<a id="bookmark1"></a><sup><a href="Chapter0X.xhtml#footnote1">1</a></sup>
They are quite handy, but must always be manually crafted