What California case law can I use to prove parental alienation syndrome? What can I use to prove parental alienation syndrome?

It is not as much a case you need to "prover" parental alienation, but rather you need to prove that the other parent is engaging in a set of behaviors designed to alienate your child from you. Those behaviors include making derogatory statements about you to the child, convincing the child that he/she has something to fear when around you, preventing the child from communicating with you, etc. Ordinarily, a litigant will hire a psychological expert to testify about the behaviors observed in the other parent to help make their case. These are difficult cases to make in Court, because many of the alienating behaviors are subtle, and it is often hard to "prove" that a child's reticence to see one parent was caused by the actions of another parent. Finally, realize that the psychological literature on parental alienation (not a syndrome, but a set of behaviors) requires that a psychologist first determine that there is no valid reason for the estrangement of a parent from a child. So, to even get to an analysis of parental alienation, you have to first show that nothing done by you would be a valid source of "estrangement" from the child.