2 mishnayot! The administration of witnesses taking a false oath of testimony, apparently along with an oath that they know nothing about what they're being asked to testify about - perhaps swearing falsely, which may or may not entail an offering to atone for it. That requirement may depend on the specifics of the oath. Also, what about testimony about one's status -- and the oath taken in that context. Plus, the significant difference between a case of status that involves a kohen to adjudicate and administer an oath - as compared to murder (for example), in court.