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

Brosnahan, Leger. "The Pendant in the Chaucer Portraits." 26 (1992): 424-31.
The pendant in Chaucer's portrait is not an ampullae but a penner, as comparison to other ampullae shows. The portrait in the manuscript was probably drawn from a free-standing bust and had to be made disproportionate in size in order to fit in the space available. The penner was removed from the belt and turned into a pendant so that it would more easily be recognized as a sign of Chaucer's profession.

Davis, R. Evan. "The Pendant in the Chaucer Portrait. "17 (1982): 193-95.
The pendant Chaucer wears in all of his portraits may be an ampulla filled with the diluted blood of St. Thomas a Becket and a sign of a pilgrimage to his shrine.

McGregor, James H. "The Iconography of Chaucer in Hoccleve's De Regimine Principum and in the Troilus Frontispiece." 11 (1977): 338-50.
The picture of Chaucer in Hoccleve was created after his death and displays specific ideas of Chaucer's purpose for writing. The frontispiece for Troilus and Criseyde may have been painted during Chaucer's life, but there is no way to decide conclusively. Hoccleve presents Chaucer as a poet who has arrived at the end of poetry: he is also a philosopher. Chaucer is also a good counselor, so Hoccleve presents an abridged Melibee, but he distorts the sense so that Chaucer becomes a counselor to princes. The portrait of Chaucer Hoccleve presents, then, is designed to inspire the prince. Chaucer is also presented as the instructor to the prince in the frontispiece to Troilus and Criseyde. Both portraits present Chaucer in a nationalistic sense, suggesting that his most important role is that of presenting philosophy to the ruler, thereby encouraging peace.