When writing a series of fiction books in which characters, universe, and events are closely related, is it a common practice in English publications to provide a footnote kind of reference, for example:
A key character A meets a key character B in volume 1.
In volume 2 character A is telling C about meeting B.
I am wondering if at the end of the 2nd sentence somewhere in the volume 2 it is common practice to add a footnote along those lines:
Character A met B in Volume 1, Chapter X, Section Y.
Or is it normally left to the reader to know and remember what volume 1 read?