1. I. Aalbersberg and E. Welzl. Trace languages defined by regular string languages. RA IRO Inform.Théor. Applic., 20:103–119, 1986.
2. A. Bertoni, G. Mauri, and N. Sabadini. Algebra, Combinatorics and Logic in Computer Science, volume 42 of Math. Soc. Janos Bolyay, chapter Unambiguous Regular Trace Languages, pages 61–100. Elsevier, 1985.
3. J.R. Büchi. On a decision method in restricted second order arithmetic. In E. Nagel and al., editors, Logic, Methodology and Philosophy of Science, Proc. 1960 Intern. Congr., volume 6, pages 1–11. Stanford Univ. Press, 1960.
4. J.R. Büchi. Weak second order logic and finite automata. Z. Math. Logik Grundlagen Math., 6:66–92, 1960.
5. C. Choffrut and L. Guerra. Logical Definability of Some Rational Rrace Languages. Math. Syst. Theory, 28:397–420, 1995.