a) Church Law

Brundage, James, Law, Sex, and Christian Society in Medieval Europe, (Chicago & London: University of Chicago Press, 1987) Must now be the standard work on the subject.
Gauthier, Albert, "La sodomie dans le droit canonique medieval" in L'Erotisme au Moyen Age: Etudes presentees au IIe Colloque de l'Institut d'Etudes Medievales, 3-4 Avril 1976, ed. Roy, Bruno (Montreal: Ed. Aurore, 1977), pp. 109-122
Goodich, Michael, "Sodomy in Ecclesiastical Law and Theory", Journal of Homosexuality 1:3 (1976), pp. 427-434 Looks at penitentials, patristics, canons, episcopal instructions to the clergy.}
Laeuchli, Samuel, Power and Sexuality: The Emergence of Canon Law at the Synod of Elvira, (Philadelphia: 1972)