Gittin 10: When Mishnayot Need Help from Gemara

2 mishnayot: First, the question of witnesses of "Kutim" - which usually invalidates a document, with exceptions, of course. Plus, an emendation of the mishnah by the Gemara. Also, documents that are produced in non-Jewish courts are valid - with exception. Plus, "dina de-malkhuta dina" - the law of the land is the law. Plus, speech as speech acts.