Niemeyer, Smith & Katz (2016) document a general asymmetry in research-software citation: software is used in science but rarely cited the way papers are

software-citationforce11research-softwarecitation-historyhistory-of-computing

Writing a position paper for the FORCE11 Software Citation Working Group, Kyle E. Niemeyer, Arfon M. Smith & Daniel S. Katz state the problem plainly: "The scientific community uses citation to acknowledge traditional research results published in archival journals and conferences, but no such accepted standard exists to credit the considerable efforts that go into software—and most research software is not cited." The paper itself never names ChainQueen, the Material Point Method, or automatic differentiation; it is a general argument about scientific publishing practice, not an empirical study of any specific paper.

This establishes "software gets used but not cited, while papers get used and cited" as a recognized, named asymmetry in computational research generally — a standing phenomenon rather than one paper's idiosyncratic choice. ChainQueen's split-by-category citation practice is one checkable instance of it, sharpened further by also citing its own prior-authored software formally while leaving uncredited third-party infrastructure out — a distinction Niemeyer, Smith & Katz's own framing does not draw, since their claim is about software broadly rather than about a split between claimed and unclaimed software. The paper's own empirical backing for the quoted sentence is Pan, Yan, Wang & Hua's 2015 Journal of Informetrics study — the citation the sentence itself ends with ("[Pan et al., 2015]") — which was not independently read this session; Howison & Herbsleb's CSCW 2011 study is cited elsewhere in the paper for a different point (interview and survey evidence that increased citation would drive software development and sharing). This note rests on the position-paper statement alone, not on a measured finding.