1. A. P. Watt and Son Records, 1861–1971 bulk (1880–1949), Berg Collection of English and American Literature, New York Public Library (cited in the endnotes as A. P. Watt & Son [BC]).
2. A. P. Watt Records #11036, Rare Book Literary and Historical Papers, The Wilson Library, University of North Carolina at Chapel Hill (cited in the endnotes as A. P. Watt [UNC]).
3. Company No: 166272; JM Burghes and Company Ltd. Incorporated in 1920. Dissolved Between 1920 and 1932, BT 31/25797/166272, National Archives, Kew (cited in endnotes as National Archives, Kew).
4. Washington Irving papers, 1759–1898, bulk (1805–1866), Archives and Manuscripts Division, New York Public Library (cited in the endnotes as Washington Irving papers).
5. “Advertisement.” Notes and Queries 87 (1851): 527–528.