Ala. Code § 12-21-65: Proof of Unwritten or Common Law of Other States and Territories.

The unwritten or common law of any other state of the United States, or of the territories thereof, may be proved as facts by parol evidence, and the books of reports of cases adjudged in the respective states purporting to be the official reports thereof or to have been published under the authority of the state or as a part of the national reporter system or of any universally accepted system of reports of decided cases and the works of commentators of recognized authority on the law of the particular state involved may also be admitted in evidence in proof of such unwritten or common law.