Kent's Writing History (1941) names the term 'diplomatics' in the same bibliographical note, crediting it to Wilhelm Bauer's book recommended as Bernheim's successor

sherman-kentdiplomaticsbernheimhistorical-methodauxiliary-sciencescross-domain-bridge

Kent's Writing History (1941) names "diplomatics" in the same bibliographical note, crediting it to Bauer's recommended successor to Bernheim

Immediately after citing Bernheim's Lehrbuch as "still crying for a translator," Sherman Kent's bibliographical note (printed pp. 110-111 of the 1941 first edition) continues by recommending its successor: "it has been largely superseded by: Wilhelm Bauer, Einfuhrung in das Studium Geschichte (2nd rev. ed., Tubingen, 1928). While covering the theoretical side of historical method, this book also goes deeply into the purely mechanical aspects of research: how to solve problems of chronology, paleography, diplomatics, as well as how to deal with subtler critical problems."

This is the word "diplomatics" itself, in Kent's own 1941 book, named alongside chronology and paleography as one of the "mechanical aspects of research" covered by the text he recommends as the up-to-date successor to Bernheim. Kent does not develop or define the term — this is a one-word mention inside a book recommendation, not substantive engagement with Mabillon's discipline or the External-Criticism auxiliary-sciences it belongs to. It establishes only that the term, and the cluster of document-authentication disciplines around it, was present in the reading list of Kent's own 1941 book.