The Chaucer Review: An Indexed Bibliography (Vols. 1-30)

Morgan, Gerald. "Boccaccio's Filocolo and the Moral Argument of the Franklin's Tale." 20 (1986): 285-306.
The idea of generosity presented in the Franklin's Tale is present in the sources for the tale. Chaucer's mastery of rhetoric does come through clearly in the tale, and he definitely adopts the generosity present in his sources. The tale distinguishes between vows, oaths, and promises. When Arveragus agrees that Dorigen must keep her word to Aurelius, he reveals that he esteems Dorigen's promises as much as his own. Dorigen faces a moral dilemma between suicide, a non-option for medieval Christians, and infidelity, also a non-option for a faithful woman. Arveragus loves Dorigen not jealously but with friendship, and so is willing to sacrifice his honor to prevent her from breaking her word. The Franklin's Tale thus reveals Chaucer's interest in morally problematic situations.

Rosenberg, Bruce A. "The Bari Widow and the Franklin's Tale." 14 (1980): 344-52.
Folklore studies indicate that two authors in different places are unlikely to create similar complex tales. Thus, Boccaccio's Filocolo and Chaucer's Franklin's Tale most likely come from a common source--the "Widow of Bari." Although the surface details differ between the "Widow of Bari" and Chaucer's Franklin's Tale, the motifs are similar and occur in the same order. Chaucer adds an emphasis on time to the analogues, thereby increasing the realism of the characters.