In https://github.com/pysal/pysal/blob/master/doc/source/developers/docs/index.rst#id24
we have:

One possible solution is to use an anonymous reference on any subsequent duplicates, signified by a single underscore with no brackets. Another solution is to put all document references together at the bottom of the document, rather than listing them at the bottom of each class, as has been done in some modules.

Can someone link to an explicit example where we have done this so others can update their modules accordingly?