Rudolf Oldenbourg. Thomas de Keysers Tätigkeit als Maler. Leipzig, 1911, pp. 21, 76, 84, no. 98, pl. IV, as in the collection of Ed. R. Bacon, New York; considers it an apparently autograph replica of the version now in the Allentown Art Museum, Allentown, Pennsylvania.
James B. Townsend and W. Stanton Howard. Memorial Catalogue of Paintings By Old and Modern Masters Collected by Edward R. Bacon. New York, 1919, p. 148, no. 184, as formerly in the collection of Sir George Donaldson, London.
Ann Jensen Adams. "The Paintings of Thomas de Keyser (1596/7–1667): A Study of Portraiture in Seventeenth-Century Amsterdam." PhD diss., Harvard University, 1985, vol. 3, pp. 19–20, no. 5 Version 1, ill., as location unknown; judging from a photograph, states that it appears to be an inferior copy of the version now in Allentown; notes that since the identity of the sitter is unknown, the meaning of the shell is impossible to interpret with certainty, but adds that the shell included in a portrait of Jan Govertsz van der Aar by Hendrick Goltzius (1603; Museum Boijmans Van Beuningen, Rotterdam) is thought to refer to the sitter's collection of shells.
Inaugural Exhibition of Old Master Paintings. Exh. cat., Otto Naumann. New York, 1995, unpaginated, ill. (color), includes it among pictures sold by him in 1994 and identifies it as the pendant of the "Portrait of a Woman Holding a Balance" (MMA, 2005.331.6).
Old Master Paintings. Sotheby's, London. July 5, 1995, p. 252, under no. 295, mentions, under the entry for the pair of pendants now in a private collection, Switzerland, three additional versions of the man's portrait, two of which seem to be the MMA work.
Lawrence W. Nichols in Hendrick Goltzius (1558–1617): Drawings, Prints and Paintings. Exh. cat., Rijksmuseum, Amsterdam. Zwolle, The Netherlands, 2003, p. 330 n. 115, calls it "A Conchologist Holding a Nautilus Shell," mentioning it among portraits of shell collectors by Dutch artists.
Walter Liedtke in "Recent Acquisitions, A Selection: 2005–2006." Metropolitan Museum of Art Bulletin 64 (Fall 2006), p. 36.
Walter Liedtke. Dutch Paintings in The Metropolitan Museum of Art. New York, 2007, vol. 1, pp. x, 394–400, no. 98, colorpl. 98, fig. 95, dates it and its pendant about 1625–26.
Esmée Quodbach. "The Age of Rembrandt: Dutch Paintings in The Metropolitan Museum of Art." Metropolitan Museum of Art Bulletin 65 (Summer 2007), pp. 65, 67.