Schoenberg's 1946 papers explicitly frame themselves as continuing a named actuarial literature on osculatory interpolation, crediting W. A. Jenkins (1926) and T. N. E. Greville (1944) as direct predecessors

schoenbergb-splinesplinesgraduationactuarial-scienceosculatory-interpolationhistory-of-mathematicspriority-claim

Early in Part A's introduction, Schoenberg writes: "we mention especially the fundamental work of W. A. Jenkins and the valuable systematization of the subject by T. N. E. Greville." The attached footnote gives full actuarial citations: W. A. Jenkins, "Osculatory interpolation: New derivation and formulae," Record of the American Institute of Actuaries, 15, 87 (1926); and Thomas N. E. Greville, "The general theory of osculatory interpolation," Transactions of the Actuarial Society of America, 45, 202–265 (1944). Schoenberg states the paper's first aim is "to carry through to a certain stage of completion the important actuarial work concerning polynomial approximations," and adds that the work "will answer Mr. Greville's conjecture" from that same 1944 paper.

Part B (also 1946) restates the framing in its own introduction — "we wish to carry further the important actuarial work on the subject of osculatory interpolation" — and includes a footnote translating its vocabulary into Greville's directly: "Greville's adjectives 'ordinary' and 'modified' agree respectively with our 'ordinary' and 'smoothing.'" A separate Part A footnote cites a third actuarial paper tying "graduation" to the same formula family: G. J. Lidstone, "Note on the computation of terminal values in graduation by Jenkins' modified osculatory formula," Transactions of the Faculty of Actuaries (Scotland), 12, 277 (1930).

This is a stronger claim than a borrowed word (see claim-schoenberg-1946-part-a-title-glosses-graduation-as-smoothing): both papers state a specific intellectual debt, name the papers being extended, and answer a named open conjecture from that literature.