i have a book thats called scary stories to tell in the dark.i have all three books,they are scary stories,more scary stories and scary stories 3.part 2 has some stuff about the bloody mary stuff and the mirror thing.bloody mary has other names,like mary worth,or mary jane.in my book it says,HERE IS HOW GHOST HUNTERS TRY TO RAISE A GHOST:
1.they find a quiet bathroom,close the door,and turnoff the lights.
2.while they stare at ththier face in the mirror,they repeat the ghost's name,usually forty-seven times or a hundred times.If any ghost will do,they say ''any ghost''in place of a name.If they do manage to raise one,it's face will slowly replace thier face in the mirror.
some say a ghost is likely to be angry at being disturbed.If it get's angry enough,they say,it will try to shatter the mirror and come right into the room,but u could always turn on the light to send it away.