Source of The Constitution of the United States is the National Archive.
"Note: The following text is a transcription of the Constitution as it was inscribed by Jacob Shallus on parchment (the document on display in the Rotunda at the National Archives Museum.) The spelling and punctuation reflects the original."
"Note: The capitalization and punctuation in this version is from the enrolled original of the Joint Resolution of Congress proposing the Bill of Rights, which is on permanent display in the Rotunda of the National Archives Building, Washington, D.C"