Hurrah! For arguably the first time since 3001, my adoring fans count references genre fiction! 
This got me to thinking, what's next? Are there any quadruple figure references passed The 4400, or am I going to have to wait. Off the top of my head I can't get beyond Warhammer 40,000, which frankly is less than encouraging.
Update: Just remembered Terror From The Year 5000, so that's a weight off my mind.
 Or at least it will until someone actually gets to read this, at which point it will no longer be true. It's all very existential; if a sci-fi fan makes an obscure reference, and no-one hears it, is he still desperately sad?