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

Maltman, Sister Nicholas, O. P. "The Divine Granary or the End of the Prioress's 'Greyn.'" 17 (1982): 163-70.
In her tale the Prioress refers to the Sarum breviary and the Mass of the Holy Innocents. In the response to the Sarum liturgy, the grain represents St. Thomas a Becket's martyrdom, and specifically the soul "winnowed" (165) from the body. Chaucer chose the grain for its connection with the Holy Innocents and St. Thomas, both of whom are associated with martyrdom. The grain on the boy's tongue physically represents his soul.

Pigg, Daniel F. "Refiguring Martyrdom: Chaucer's Prioress and Her Tale." 29 (1994): 65-73.
The Prioress must be read outside the context of her portrait in the General Prologue since the General Prologue was written after the Prioress's Tale. Also, in her tale the Prioress uses a different definition of martyrdom. The early Church thought of martyrdom in two ways, the physical death and the preservation of virginity which was often associated with taking monastic vows. Invoking the Virgin, the Prioress authorizes the tale she tells by denying that it is her own. In the tale, the Prioress refigures martyrdom several ways. She refers to the Feast of the Holy Innocents, emphasizes the virginity of the little boy, and reminds the pilgrims of Hugh of Lincoln's martyrdom.