Larry E. Morris summarizes the sources pertaining to the experiences of the Three and Eight Witnesses.
Larry E. Morris, A Documentary History of the Book of Mormon (New York, NY: Oxford University Press, 2019), 370–372, 415–422
THE EVER-INTRIGUING MARTIN Harris is such a prominent player in the origin of the Book of Mormon that at times he threatens to overshadow Joseph Smith. And while Harris naturally took center stage in the cases of the learned professor of the East and the disappearance of the 116 pages, it is somewhat surprising—given the strong personalities of both Oliver Cowdery and David Whitmer—that Harris garners so much attention in discussions and debates centering on the three witnesses.
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THE STATEMENT OF Cowdery, Whitmer, and Harris, which spoke of the voice of God and an angel coming down from heaven with plates, was on one hand impressive confirmation of what Joseph Smith had been claiming all along, but on the other, a pronouncement propelled beyond the scope of academic analysis by those very "nonempirical" details. The statement of the four Whitmer brothers, Hiram Page, and the three Smiths was quite a different matter—saying nothing about a divine voice or an angelic visitor. "As many of the leaves as the said Smith has translated we did handle with our hands; and we also saw the engravings thereon"—that was the deposition of the eight neatly summed up.