Tina, a hospital administrator, and Diane, a self employed landscaper, are California Registered Domestic Partners. They began living together in 2000. Before they registered in 2006, Tina went to a lawyer and had a pre-registration agreement prepared. The agreement states that all earnings of both partners during the registered partnership will be separate property. The agreement refers to exhibits containing lists of each person's assets and debts, but no exhibits are attached. The agreement contains a provision stating that Diane has been advised she should consult an attorney and that she is signing the agreement voluntarily. Tina and her lawyer signed the agreement. Ten days before Tina and Diane registered, Tina gave the agreement signed by Tina and her lawyer to Diane. Diane told Tina she would sign the agreement. Diane did not consult a lawyer. Diane signed the agreement two months after she and Tina registered. Tina and Diane are now separating. Tina wants to enforce the agreement and Diane wants to get out of it. Is the agreement signed by Tina and Diane an enforceable agreement?

What authorities support each party's position?