I've seen this latin term in footnotes several times and still don't know the meaning of it. It is usually used like this:
 About this, see John Smith 2003, ad indicem.
or like this:
 Jane Smith 2006, 98-101, and ad indicem.
What does it mean? Does it mean "there are too many pages in this book related to this topic. I don't want to list them all. Just go check the index yourself"?