Gear puller will work but (1) you have to put something in/on the BB spindle to push against - a partially inserted crank bolt sticking out proud of the crank arm will work, and (2) you may need some additional plan for holding the 'fingers' of the puller on the back of the arm - a large pair of vise grips or a clamp or a friend holding a pair of channel lock pliers, just to keep the fingers from slipping off the back of the arm.