1. M. Ajtai, ‘ε 1 1 formulae on finite structures', Annals of Pure and Applied Logic 24 (1983), 1–48.
2. D. A. Barrington, ‘Width 3 Permutation Branching Programs', Technical Memorandum TM-291, M.I.T. Laboratory for Computer Science, Dec. 1985.
3. D. A. Barrington, ‘Bounded-width polynomial-size branching programs recognize exactly those languages in NC 1', Proc. 18th ACM STOC, 1986, 1–5.
4. D. A. Barrington, ‘Bounded-width branching programs', Ph.D. thesis, Dept. of Mathematics, M.I.T., May 1986. Available as Technical Report TR-361, M.I.T. Laboratory for Computer Science.
5. A. Borodin, D. Dolev, F. E. Fich, and W. Paul, ‘Bounds for width two branching programs', Proc. 15th ACM STOC, 1983, 87–93.