Article 4, Section 2, Clause 1
St. George Tucker, Blackstone's Commentaries 1:App. 3651803
This article, with some variation, formed a part of the confederation: we have in another place supposed, that the states retain the power of admitting aliens to become denizens of the states respectively, notwithstanding the several acts of congress establishing an uniform rule of naturalization. But such denizens, not being properly citizens, would not, I apprehend, be entitled to the benefit of this article in any other state. They would still be regarded as aliens in every state, but in that of which they may be denizens. Consequently, an alien before he is completely naturalized, may be capable of holding lands in one state, but not of holding them in any other.
The Founders' Constitution
Volume 4, Article 4, Section 2, Clause 1, Document 11
The University of Chicago Press
Tucker, St. George. Blackstone's Commentaries: With Notes of Reference to the Constitution and Laws of the Federal Government of the United States and of the Commonwealth of Virginia. 5 vols. Philadelphia, 1803. Reprint. South Hackensack, N.J.: Rothman Reprints, 1969.
Easy to print version.