1. A. V. Aho, D. S. Hirschberg and J. D. Ullman,Bounds on the complexity of the longest common subsequence problem, J. Assoc. Comput. Mach. 23(1) (Jan. 1976), 1–12.
2. A. V. Aho, J. E. Hopcroft, and J. D. Ullman,The Design and Analysis of Computer Algorithms, 2nd printing, Addison-Wesley, Reading, Mass., 1976.
3. V. L. Arlazarov, E. A. Dinic, M. A. Kronrod, and I. A. Faradzev,On economic construction of the transitive closure of a directed graph. Dokl. Akad. Nauk SSSR 194 (1970), 487–488 (in Russian), English transl. in Soviet Math., Dokl. 11, 5 (1970), 1209–1210.
4. V. Chavatal, D. A. Klarner, and D. E. Knuth,Selected combinatorial research problems, STAN-CS-72-292, Stanford Univ., Stanford, Calif. 1972, p. 26.
5. V. Chvatal and D. Sankoff,Longest common subsequences of two random sequences. STAN-CS-75-477, Stanford Univ., Stanford, Calif., Jan. 1975.