Sakarovitch, Jacques (September 1987). "Easy multiplications I. The realm of Kleene's theorem". Information and Computation. 74 (3): 173–197. doi:10.1016/0890-5401(87)90020-4. Zbl0642.20043.
Sakarovitch, Jacques (September 1987). "Easy multiplications I. The realm of Kleene's theorem". Information and Computation. 74 (3): 173–197. doi:10.1016/0890-5401(87)90020-4. Zbl0642.20043.