I assume that like many older cars that have not had the drum off in like forever, the drum is seriously rusted to the flange. It will takes lots of patience, penetrating oil (don't get it inside the brake shoe area, it may deteriorate the boots on the cyclinder), a hammer and a puller that can span the drum. Usually this last item is hard to find, so I usually use two or three large screwdrivers to wedge between the backing plate and the edge of the drum. Be careful with this screwdriver approach because it's easy to distort the backing plate. Apply force to the drum, apply penetrating oil to the center of the hub, apply a hammer to the center of the hub. The idea is to break loose the rust. Before you start this wedging and hammering, though, clear away as much rust as possible from the area where the drum will want slide off. A file or screwdriver blade helps. There's no use trying to slide the drum over rust that's visible and easily accessible. Before you start, see if you can check the grease seal on the back of the stub axle assembly. If the seal has a hole in it from rust, you get to replace the stub axle also, so maybe the best thing is to see if you can remove the parking brake cable, the hydraulic cable, and expect to replace the drum and cylinder along with the brake shoes. You'll probably have to replace the drum anyway, so smash it with a big hammer. The bolts that hold the stub shaft to the control arm are probably not accessible from outside the drum. Sorry about your luck. Sometimes some gentle heat from a torch will loosen the rust, but don't do that if you've use penetrating oil unless you like to see flames. The penetrating oil approach will take a long time, lot's of moving the wedges and lots of hammering. But, eventually you'll see the drum start to move.