Donald E. Knuth, Knuth meets NTG members, NTG: MAPS. 16 (1996), 38–49. Reprinted as Questions and Answers, III, chapter 33 of Digital Typography. str. 648.
Knuth & Plass 1981;Plass,Michael F(1981).„Breaking Paragraphs Into Lines”.Software: Practice and Experience11: 1119–84.DOI:10.1002/spe.4380111102. Reprinted as „Chapter 3”.Digital Typography.pp.67–155.
Donald E. Knuth. Typesetting Concrete Mathematics, TUGboat 10 (1989). str. 31–36. str. 342. Reprinted as chapter 18 of Digital Typography. str. 367–378.