That's the one. http://forum.bodybuilding.com/showthread.php?t=148036063&page=1
It's a good program nonetheless, which is to say, SL5x5 is a good program and it doesn't hurt to do some additional accessory movements.
Depends on what you want really, but some good ones I have are:
"Beyond Brawn", Stuart McRobert (general, good tips)
"Greyskull LP", Johnny Pain (nothing spectacular, but the program is very close to IFC 5x5 which you're running, right?)
"Maximum Muscle" & "Squat Every Day", Matt Perrymann (both are really good, but might not be you're looking for. Not strictly related to lifting. Covers other areas such as biology, neuroscience, philosophy, etc)
"Supertraining", Yuri Verkhoshansky & Mel C. Stiff (looks great. haven't started yet)
Some off Jason Ferrugia's work. His books are more bro-ey than scientific but there are some good stuff, especially his Renegade Diet.
I'm actually doing the basic greyskull workout with different accessory work. I think I am going to make a switch to 5/3/1 or something similar soon, since linear progression with bench and press just isn't working any longer.