Sifrei Devarim 239

¹(Devarim 22:20) "And if the matter were true — if virginity were not found in the maiden": This tells me only of natural coitus. Whence do I derive the same for unnatural coitus? From "And if the matter were true." ²"if virginity were not found in the maiden": i.e., if there were no witnesses to refute the witnesses of the husband. ³( Ibid . 21) "Then they shall take out the maiden to the door of her father's house." This tells me only of her having a father and a door of her father's house. Whence do I derive (the same for) a maiden who lacks either one? From "Then they shall take out the maiden" (to be stoned) — in any event.