5...Bg7 The only opening book I have is Batsford Chess Openings(1982) its outdated so I don't look at it. I recently bought The Complete Chess Workout(1200 puzzles) Chess Gems:1000 Combinations You Should Know and Silman's Complete Endgame Course. Actually I have one other opening book. "Unorthodox Chess Openings". I also have The Life and Games of Mikhail Tal.