Bo Johnson, "Form and Message in Lamentations," Zeitschrift für die Alttestamentliche Wissenschaft 97.1 (1985): 58-73.

Johnson argues that the five chapters of Lamentations offer a carefully designed structure, underlined by the alphabetical acrostic. The first
four chapters consist of a "fact half," a "culmination," and an "interpretation half." The central point of Lamentations lies at the center of the central lament (ch. 3), where the theological message is revealed: the distress is a punishment aiming at rehabilitation, not at definitive rejection. The concluding fifth chapter is formed as a prayer addressed to the Lord, following the basic 22-stanza alphabetic acrostic pattern but without the letters. Johnson suggests that chapter 5 is the oldest part of the work.