Here are a number of links to an important articles and essays on the book of Jonah.
1. T. D. Alexander, Jonah and Genre Tyndale Bulletin 36 (1985), 35-59.
2. D. J. Wiseman, Jonah's Nineveh Tyndale Bulletin 30 (1979), 29-52.
3. G. Ch. Aalders, The Problems of the Book of Jonah (1948).
4. Paul Ferguson, Who Was the 'King of Nineveh' in Jonah 3:6? Tyndale Bulletin 47 (1996), 301-314.
5. Paul J. N. Lawrence, Assyrian Nobles and the Book of Jonah Tyndale Bulletin 37 (1986), 121-132.
6. John H. Walton, The Object Lesson of Jonah 4:5-7 and the Purpose of the Book of Jonah Bulletin for Biblical Research 2 (1992), 47-57.
7. Other articles and books are listed HERE.