One of those endgame compositions that can drive a person crazy. Give it a shot, though. Composed by Halberstadt.
One of many variations, but it gives you the idea:Check the king so you can get the bishop in the game and then push him over toward your king for the mate. 1.Qg7+ Kc2 2.Qc3+ Kd1 3.Qd3+ Kc1 4.Qc4+ Kd2 5.Qf4+ Ke1 6.Qg3+ Kd2 7.Bg4 Qh8 8.Qf2+ Kc1 [8...Kd3 9.Bf5#] 9.Qe1+ Kb2 10.Qd2+ Kb1 11.Bf5+ Ka1 12.Qc1+ Ka2 13.Qb1#