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Whole-book author: Oscar Levin. No separate chapter author is credited in the inspected section.

Online front matter: discrete.openmathbooks.org/dmoi3/frontmatter.html

The author's institutional publication list dates the third edition to 2018. The online front matter displays 12 August 2025 without identifying that date as the edition's original publication date.^{[ref] [ref]}

Online text: discrete.openmathbooks.org/dmoi3/sec_counting-binom.html

Cited passages: §1.2, Lattice Paths, step-position encoding; Binomial Coefficients, counting interpretations and recurrence; Pascal’s Triangle, indexing and edge values. The third edition’s 2018 publication year is distinct from the online front matter’s displayed date of 12 August 2025.