How have the courts interpreted the burden of proving that a reconveyance was not done by mistake?

Second, appellant claims that the court erred in ruling that he "had to prove that the reconveyance was not done by mistake." Appellant cites no portion of the record to show that this was the court's ruling. He also cites no legal authorities with respect to the applicable burden of proof. His argument is waived because it is not supported by citations either to the record or to legal authority. (Schubert v. Reynolds (2002) 95 Cal.App.4th 100, 109.)