This one is a long paper that is very informative about mercury poisoning=autism. If you go to the 3 or 4th page, it starts listing autism characteristics paired beside the mercury poisoning symptoms. You can see that they are the same http://www.autism.com/ari/mercurylong.html
This is an Autism-Mercury group. It is very informative and the "FILE" section has informative papers regarding autism and mercury. Someone also compiled some success stories. People from the group compiled important information that can save you lots of time searching for information on Autism-mercury.
Good luck...and we did both ABA and floortime. I think that one on one is very good for children. Regardless of the therapy that you select, I think that is an important thing to note between all the therapies that are successful. They all have one on one with many hours of keeping the child engaged in common. (Son-rise, floortime, ABA, DTT, DTT-NET, VB) And they have all been shown to be successful. Best wishes!