Most of these works in the following Bibliography predate 1920s and thus reflect the scholarship of that day. Which wouldn’t include for example: the finding of Tobit among the Dead Sea Scrolls which meant the original language of Tobit had yet to be proven conclusively, (not to say that many didn’t assume such an origin). But, more importantly every work here is free, found online via GoogleBooks, The Web Archive, or if need be from various websites which have hosted them.
For the most part I started from Carey A. Moore’s Bibliography and used the Bibliography from several of the works mentioned here, I then sought out which of the works that I could find. If anyone would like to suggest a book or books which should be added, please leave a reply.
1888–89 “Tobit’s Dog.” JQR 1: 288.
1893 “Tobit and Genesis.” JQR 5: 348–50.
Ball, Charles J.
C.1886 “The Book of Tobit.” The Apocrypha of the Old Testament, with Historical Introductions and Notes and Explanatory. New York: Charles Scribner’s Sons.
1923 Aramaic Papyri of the Fifth Century B.C. Oxford: Clarendon. Pp. 204–48.
1907–14 “Tobias.” The Catholic Encyclopedia, 15 vols. New York: Appleton. 14: 749–53.
1899-1907 ‘Tobit .’ in Encyclopaedia Biblica, 4 vols. London: A and C Black. 4: 607-617
Fitzmyer, Joseph A. SJ.
Fuller, John M.
1888 Tobit. Apocrypha of the Speaker’s Commentary, ed. H. Wace, 1: 149–240. London: John Murray.
Harris, J. Rendel, Agnes S. Lewis, and Frederick C. Conybeare
1913 The Story of Ahikar. APOT, ed. Robert H. Charles. Oxford: Clarendon. 2: 715–84.
1898 Ahikar from the Syriac, Arabic, Armenian, Ethiopic, Greek and Slavonic Versions. London: C.J. Clay and Sons.
James, Montague R.
1897 Apocrypha Anecdota, 2d ser., Texts and Studies 5/1. Cambridge: Cambridge University Press.
1913 Aramaic Incantation Texts from Nippur. The Museum Publication of the Babylonian Section, vol. 3. Philadelphia: University of Pennsylvania.
1903 Demonology. JE, ed. Isidore Singer, 12 vols. New York: Funk and Wagnalls. 4: 514–20.
Marshall, John T.
1898–1904a “Asmodeus .” HDB, 5 vols. Edinburgh: Clark. 1: 172–73.
1898–1904b “Tobit, the Book of.” HDB 4: 785–89.
Moulton, James H.
1899–1900 “The Iranian Background of Tobit.” ExpTim 11: 257–60.
1913 “The Magian Material of Tobit.” Early Zoroastrianism. London: Williams and Norgate. Esp. pp. 99, 332
1878 The Book of Tobit: A Chaldee Text from a Unique Manuscript in the Bodleian Library, with Other Rabbinical Texts, English Translations and the Itala. Oxford: Clarendon.
Nickelsburg, George W.E.
Oesterley, William O. E.
1914 “Tobit.” The Books of the Apocrypha: Their Origin, Teaching and Contents. New York: Ravel. Pp. 349–71.
1935 “Tobit.” An Introduction to the Books of the Apocrypha. London: SPCK. Pp. 161–71.
Sayce, Archibald H.
1908 Tobit and the Babylonian Apocryphal Writings. Philadelphia: J. B. Lippincott. Pp. i–xiii, 1–26.
Simpson, David C.
1913a “The Book of Tobit .” APOT 1: 174–241. Oxford: Clarendon Press.
1906 “Tobit, Book of.” JE, eds. Isidore Singer et al.; 12 vols. New York: Funk and Wagnalls. 12: 171–72.
Wicks, Henry J.
1915 The Doctrine of God in the Jewish Apocalyptic and Apocryphal Literature. London: Hunter and Longhurst (Repr. by KTAV in 1971).
 This might not be the actual work, but I have been unable to find the book with that Title or its other title Variorum Apocrypha
 According to Oesterley’s The Books of the Apocrypha… this book was republished in 1914, with more content. But I have been unable to find this