The article mentions the Project Oberon book and the piece list algorithm, which goes back to Xerox PARC's Bravo editor. Coincidentally I came across this paper

The article mentions the Project Oberon book and the piece list algorithm, which goes back to Xerox PARC's Bravo editor. Coincidentally I came across this paper recently about different data structures for text editors, which covers the piece list algorithm but also several others: "Data Structures for Text Sequences" (1998), Charles Crowley (https://www.cs.unm.edu/~crowley/papers/sds.pdf https://www.cs.unm.edu/~crowley/papers/sds.pdf).