Whitman, Walt. "Letter to Nathaniel Bloom and John F.S. Gray." Letter to Nathaniel Bloom and John F.S. Gray (1863): 80-85.
Holloway, Emory. Walt Whitman: An Interpretation in Narrative. New York & London: Alfred A. Knopf, 1926.
Allen, Gay Wilson. The Solitary Singer: A Critical Biography of Walt Whitman. New York: MacMillan, 1955.
Whitman, Walt. "Letter to Hugo Fritsch, Before August 7, 1863." Walt Whitman: The Correspondence 1, (1961): 123-124.
Whitman, Walt. "Letter to William D. O'Connor, September 27, 1867." Walt Whitman: The Correspondence 1, (1961): 342-343.
Miller, Edwin Haviland. "Introduction." In The Correspondence of Walt Whitman: Volume I, 1842-1867, edited by Edwin Haviland Miller. New York: New York University Press, 1961.
Whitman, Walt. "Letter to Nathaniel Bloom, September 5, 1863." Walt Whitman: The Correspondence 1, (1961): 141-143.
Whitman, Walt. "Letter to Hugo Fritsch, October 8, 1863." Walt Whitman: The Correspondence 1, (1961): 158-160.
Stansell, Christine. "Whitman at Pfaff's: Commercial Culture, Literary Life and New York Bohemia at Mid-Century." Walt Whitman Quarterly Review 10, no. 3 (1993): 107-126.
Katz, Jonathan Ned. "Love Stories: Sex Between Men Before Homosexuality." Love Stories: Sex Between Men Before Homosexuality (2001).
Karbiener, Karen. "Whitman at Pfaff's: Personal Space, a Public Place, and the Boundary-Breaking Poems of <cite>Leaves of Grass</cite> (1860)." In Literature of New York, edited by Sabrina Fuchs-Abrams. Newcastle upon Tyne, U.K.: Cambridge Scholars, 2009.
Blalock, Stephanie M. "'My Dear Comrade Frederickus': Walt Whitman and Fred Gray." Walt Whitman Quarterly Review 27, no. 1 (2009): 49-65.
The Vault at Pfaff's