Olsder and Strijbos's 1976 population-planning paper cites two 1975 Twente internal memoranda (nr. 64 and nr. 94) as its working-paper predecessors

geert-jan-olsderr-c-w-strijboshuibert-kwakernaakuniversity-of-twentepopulation-policycontrol-theorycitation-genealogynetherlands

The published version of G.J. Olsder and R.C.W. Strijbos's "Population planning; a distributed time optimal control problem" (Springer, Lecture Notes in Computer Science vol. 40, 1976, pp. 721–735) names, in its own reference list — four entries long, read via Springer's chapter landing page and corroborated against CrossRef's deposited copy of the same list, the chapter text itself being paywalled — two earlier 1975 Twente internal documents: the authors' own working paper — "Memorandum nr. 64, Twente University of Technology, The Netherlands, 1975" — and a parallel, Dutch-language Kwakernaak memorandum, "Population policy as an optimal control problem, Memorandum nr. 94, Twente University of Technology, The Netherlands, 1975." Both pre-date the 1976 conference paper and place the same optimal-control-of-population work inside the University of Twente a year earlier, in internal circulation.

These two memoranda are a genuine addition to the Twente lineage the vault already holds, not a restatement of it. claim-kwakernaak-1977-bibliography-excludes-astrom-rests-on-dutch-twente-club-of-rome-lineage reconstructs, from Kwakernaak's 1977 chapter's own CrossRef-deposited reference list, a longer run of the same program — three student project reports under the title "Bevolkingspolitiek als optimaal besturingsprobleem" (J. Jeuring, Dec. 1972; A. Bosch-de Boer, Jan. 1974; B.H. Hoeksma, Mar. 1975) and Kwakernaak's own November-1975 De Ingenieur article — but that list does not include either of these two numbered memoranda. The 1976 paper's own bibliography is therefore a second, independent window onto the 1975 state of the program, catching documents the 1977 chapter's list omits.

What the memoranda corroborate is the content and dating of the Twente research, not the disputed 1975 meeting itself: they show the population-as- optimal-control work was an active, internally-documented program in 1975, consistent with — but not evidence of — the 1975 Song Jian encounter Olsder later described (claim-olsder-account-traces-song-jian-twente-contact-to-1975-delegation-visit). That distinction between the content trail and the meeting is the same one drawn at observation-kwakernaak-1977-citation-trail-sharpens-not-resolves-1975-dating-dispute; the meeting's corroboration remains open at question-verify-song-jian-1975-twente-delegation-visit. The memoranda themselves have not been located or read directly — a Twente special- collections or Atlantis-archive route to the physical/scanned originals is a standing lead, not a resolved source.