Verse-by-Verse Commentaries:

Joyce G. Baldwin, Haggai, Zechariah, Malachi (Tyndale), Inter-Varsity, 1972.
Charles L. Feinberg, "Haggai" in The Wycliffe Bible Commentary, The Southwestern Company, 1968: 889-896.
J. Alec Motyer, "Haggai" in The Minor Prophets, Volume III (ed. T. McComiskey), Baker, 1998.
Marvin A. Sweeney, The Twelve Propets, Vol. II, (Berit Olam), Liturgical, 2000.
Pieter A. Verhoef, The Books of Haggai and Malachi (NICOT) Eerdmans, 1987.
Hans Walter Wolff, Haggai (Continental), Augsburg-Fortress, 1988. ****

Monographs, Compilations, and Studies:

Articles and Essays:

Duane L. Christensen, "Impulse and Design in the Book of Haggai," JETS 35 (1992): 445-456.
David J. Clark, "Discourse Structure in Haggai," Journal of Tranlation and Textlinguistics 5.1 (1992): 13-24.
David J. Holbrook, "Narrowing Down Haggai: Examining Style in Light of Discourse and Content," Journal of Tranlation and Textlinguistics 7.2
____ (1995): 1-12.
John A. Kessler, "The Shaking of the Nations: An Eschatological View," JETS 30 (1987): 159-166.

More Commentaries:

Elizabeth Achtemeier, Nahum-Malachi (Interpretation), Westminster John Knox, 1986.
Robert L. Alden, "Haggai" in Expositor's Bible Commentary, Vol. VII, Zondervan, 1985.
David W. Baker, Nahum, Habakkuk, Zephaniah (Tyndale), Inter-Varsity, 1988.
Walter Kaiser, Micah, Nahum, Habakkuk, Zephaniah, Haggai, Zechariah, Malachi (Mastering the Old Testament), Word Books, 1992.
J. L. Mackay, Haggai, Zechariah & Malachi (Focus on the Bible), Christian Focus, 1994.
W. Eugene March, "Haggai" in The New Interpreter's Bible, vol. VII, Abingdon, 1996.
Carol L. and Eric M. Meyers, Haggai and Zechariah 1-8 (Anchor), Doubleday, 1987.
David L. Petersen, Haggai and Zechariah 1-8 (OTL), Westminster John Knox, 1984.
J. J. Roberts, Nahum, Habakkuk, and Zephaniah (OTL), Westminster/ John Knox, 1991.
O. Palmer Robertson, The Books of Micah, Nahum, and Zephaniah (NICOT), Eerdmans, 1994.
Ralph L Smith, Micah-Malachi, (Word Biblical Commentary, 32), Word Books, 1984.
Donald J. Wiseman, "Haggai" in The New Bible Commentary, Eerdmans, 1967: 781-785.