>>19329908References are very sparce. Very. Very. Sparce. Almost non-existent. Usually, if something is happening in another game at the same time, they will make references to that game. But that's about it. Things that are referenced are more concurrent and less of something that happened prior. Games are ordered chronologically by generation, for the most part.
But, X and Y are very much a reboot. Just grab it and ignore the older games.