Clavis canonum: Selected canon law collections, 385-1234 — Online database search [internet resource]
Gero Dolezalek, Medieval Manuscripts of Canon Law and Roman Law [internet resource]
Abigail Firey, The Carolingian Canon Law Project [internet resource]
Johann Georg Theodor Grässe, Orbis Latinus [html]
Johann Georg Theodor Grässe. Orbis Latinus: Lexicon lateinischer geographischer Namen des Mittelalters und der Neuzeit. Berlin: Richard Carl Schmidt, 1909. Hosted by Columbia University.
Gregor Haloander, Modus legendi abbreviaturas. [pdf]
Gregor Haloander. Modus legendi abbreviaturas passim in iure tam civili, quam pontificio occurrentes. Rome: Typis Gulielmi Facciotti, 1623. Reprint Bononia: A. Forni, 1989. Hosted by Colby College.
Paul Halsall, Internet Medieval Sourcebook [internet resource]
Wilfried Hartmann and Kenneth Pennington, eds., The history of medieval canon law in the classical period, 1140-1234: From Gratian to the Decretals of Pope Gregory IX. [searchable fulltext]
The history of medieval canon law in the classical period, 1140-1234: From Gratian to the Decretals of Pope Gregory IX. Edited by Wilfried Hartmann and Kenneth Pennington. Washington: Catholic University of America Press, 2008. Hosted by Google books.
Karl J. von Hefele, trans. H. Leclercq. Histoire des conciles d’apres les documents originaux. [text-searchable pdf of all volumes]
Karl J. von Hefele. Histoire des conciles d’apres les documents originaux. Translated by H. Leclercq. Paris: Letouzey, 1907. Hosted by www.archive.org.
Walther Holtzmann Catalog of the Stephan Kuttner Institute of Medieval Canon Law [internet resource]
Y. Lassard & A. Koptev, The Roman Law Library [internet resource]
Giovan Domenico Mansi. Sacrorum conciliorum nova, et amplissima collectio. [pdf of all volumes]
Giovan Domenico Mansi. Sacrorum conciliorum nova, et amplissima collectio. Florence, 1759. Hosted by Documenta Catholica Omnia.
The ORB: Online Reference Book for Medieval Studies [internet resource]
Kenneth Pennington and Charles Donahue, Jr., Bio-Biblographical Guide to Medieval and Early Modern Jurists [internet resource]
Kenneth Pennington, Medieval Legal History website [internet resource]
Edward Peters, Canonlaw.info [internet resource]
Schedario Baumgarten. [pdf of vols. 1-3]
Schedario Baumgarten. Descrizione diplomatica di bolle e brevi originali da Innocenzo III a Pio IX. Riproduzione anastatica. Edited by Giulio Battelli and Gergio Pagano. Vatican: Presso l’Archivio Segreto Vaticano, 1965-1986. Hosted by the Vatican Secret Archives.
August Theiner. Disquisitiones criticae. [text-searchable pdf]
August Theiner. Disquisitiones criticae. Rome: Collegio Urbano, 1836. Hosted by Colby College.
Otto Vervaart, Rechsthistorie: A Gateway to Legal history [internet resource]