This paper investigates the structure of derivations in deterministic ETOL systems. The main theorem says that in a deterministic ETOL system each derivation of a long enough word of a special kind (the so-called f-random word) has a very strong combinatorial structure. In fact the main result of this paper is very essential for proving useful properties of deterministic ETOL languages, which is demonstrated already in a number of papers.
Ehrenfeucht, Andrzej and Rozenberg, Grzegorz, "On Structure of Derivations in ETOL Systems ; CU-CS-046-74" (1974). Computer Science Technical Reports. 45.