Original meaning
Originalists of all stripes cite "The Federalist Papers". It is fairly tenuous to suggest that this represents a good source for the original "intent": after all, Alexander Hamilton, who wrote the majority of those essays, was absent for the greater part of the Philadelphia Convention, and John Jay did not attend it at all. However, James Madison, the principal framer of the Constitution also wrote a substantial amount of "The Federalist Papers". Also, to suggest Hamilton and Jay's absence from the convention implies their ignorance as to the Constitution's original meaning is demeaning to those two men and inaccurate. The collected anti-Federalist papers, of course, will be no use at all to a person searching for the original "intent" of the framers. However, as evidence of how a reasonable person at the time would have understood the words of the Constitution, "The Federalist Papers" and the anti-Federalist essays are evidence of direct relevance.
The Federalist Papers
The authorship of seventy-three of "The Federalist" essays is fairly certain. Twelve of these essays are disputed over by some scholars, though the modern consensus is that Madison wrote essays Nos. 49–58, with Nos. 18–20 being products of a collaboration between him and Hamilton; No. 64 was by John Jay. The first open designation of which essay belonged to whom was provided by Hamilton who, in the days before his ultimately fatal gun duel with Aaron Burr, provided his lawyer with a list detailing the author of each number. This list credited Hamilton with a full sixty-three of the essays (three of those being jointly written with Madison), almost three-quarters of the whole, and was used as the basis for an 1810 printing that was the first to make specific attribution for the essays.
Madison did not immediately dispute Hamilton's list, but provided his own list for the 1818 Gideon edition of "The Federalist". Madison claimed twenty-nine numbers for himself, and he suggested that the difference between the two lists was "owing doubtless to the hurry in which [Hamilton's] memorandum was made out." A known error in Hamilton's list—Hamilton incorrectly ascribed No. 54 to John Jay, when in fact, Jay wrote No. 64—provided some evidence for Madison's suggestion.