2959c81e_ufficient_Mating_Material_Rule__2
[0] Example C [2] 
This position is also drawn, white can't mate black even with two or more bishops if his bishops move on the same color. White could win only if he had bishops on different color squares of the board. Of course this is a strange situation, white has promoted a pawn to a bishop instead of a queen, that would have easily won the game.
[E4EC] The insufficient Mating Material Rule
2